Function

Returns the total.

Example:

add(1, 2, 3, 1); // 7
add(1, 3); // 4

public after(count: number, fn: Function): Function source

import {after} from 'js-helpers/src/Function/index.js'

Creates a function that invokes fn once it's called n or more times.

Params:

Name	Type	Attribute	Description
count	number		The number of calls before func is invoked.
fn	Function		The function to restrict.

Return:

Function that invokes fn once it's called n or more times.

public alt(fn1: Function, fn2: Function): Function source

import {alt} from 'js-helpers/src/Function-Combinators/index.js'

This combinator takes two functions and returns the result of the first one if the value is defined (not false, null, or undefined); otherwise, it returns the result of the second function.

Params:

Name	Type	Attribute	Description
fn1	Function		First result function.
fn2	Function		Second result function.

Return:

Returns the result of the first one if the value is defined (not false, null, or undefined); otherwise, it returns the result of the second function

Example:

const calc = alt(identity, x => x + 1);
calc(0); // 1
calc(2); // 2

public always(value: T): Function source

import {always} from 'js-helpers/src/Function-Combinators/index.js'

Creates function which will always return passed argument. K - combinator implementation.

Params:

Name	Type	Attribute	Description
value	T		Argument that should returned back from function which was returned.

Return:

Returns function which will always return first passed argument.

Example:

always(2)(); // 2

public and(predicates: ...Function): Function source

import {and} from 'js-helpers/src/Predicate-Combinator/index.js'

Takes list of predicates and returns a one predicate, current predicate will return true only in case if all passed predicates return true.

Params:

Name	Type	Attribute	Description
predicates	...Function		List of predicates.

Return:

Predicate function.

public any(source: Array<T>, fn: Function): boolean source

import {any} from 'js-helpers/src/Array/index.js'

Checks if predicate returns truthy for any element of collection. Iteration is stopped once predicate returns truthy. Is analog some(*) function.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	The collection to iterate over.
fn	Function		The collection to iterate over.

Return:

Returns true if any element passes the predicate check, else false.

public assoc(propName: string, valueToBeSet: T, source: object): object source

import {assoc} from 'js-helpers/src/Lens/index.js'

Makes a deep clone of an object, setting or overriding the specified property with the given value.

Params:

Name	Type	Attribute	Description
propName	string		Property name
valueToBeSet	T		New value for property
source	object		Object where should be changed property value.

Return:

Clone of source with changed value.

public assocPath(path: Array<String|Number>, valueToBeSet: any, source: Object | Array): Object | Array source

import {assocPath} from 'js-helpers/src/Lens/index.js'

Updates Array or Object by given path with given value.

Params:

Name	Type	Attribute	Description
path	Array<String\|Number>		Path to property which should be changed.
valueToBeSet	any		Value which should be set by path.
source	Object \| Array		Source where should be changed property.

Return:

Object | Array

Resurns clone of object or array with applied changes.

public buildResource(src: String, args: Array<T>): String source

import {buildResource} from 'js-helpers/src/String/index.js'

Works similarly to templates. Sequentially replaces all placeholders ({0}, {1}, {2}...).

Params:

Name	Type	Attribute	Description
src	String	optional default: ''	Source for replacements.
args	Array<T>		Values for replacements.

Return:

New String with all replacements.

public camelCase(str: String): String source

import {camelCase} from 'js-helpers/src/String/index.js'

Converts string to camel case.

Params:

Name	Type	Attribute	Description
str	String		The string to convert.

Return:

Returns the camel cased string.

public castArray(valueToCast: ...T): Array<T> source

import {castArray} from 'js-helpers/src/Array/index.js'

Casts values as an array if it's not one.

Params:

Name	Type	Attribute	Description
valueToCast	...T		All values will be included in array that will be returned back.

Return:

Array<T>

Return array that will include all arguments.

public changeOrder(source: Array<T>, order: Array<number>): Array<T> source

import {changeOrder} from 'js-helpers/src/Array/index.js'

Returns array with changed order.

Params:

Name	Type	Attribute	Description
source	Array<T>		Array that should change the order.
order	Array<number>		Order Array.

Return:

Array<T>

Array with changed order.

public cloneArray(source: Array<T>): Array<T> source

import {cloneArray} from 'js-helpers/src/Array/index.js'

Will create clone of given array.

Params:

Name	Type	Attribute	Description
source	Array<T>		Array that should be cloned.

Return:

Array<T>

Cloned array.

Example:

cloneArray([1,2,3]); // [1,2,3]

cloneArray([{name: 'John'}, {name: 'Liza'}]); // [{name: 'John'}, {name: 'Liza'}]

public cloneObject(objectToClone: object): object source

import {cloneObject} from 'js-helpers/src/Object/index.js'

Will create object clone.

Params:

Name	Type	Attribute	Description
objectToClone	object		Object that should be cloned.

Return:

Clone of passed object.

public compact(source: Array<T>): Array<T> source

import {compact} from 'js-helpers/src/Array/index.js'

Creates an array with all falsey values removed. The values false, null, 0, "", undefined, and NaN are falsey.

Params:

Name	Type	Attribute	Description
source	Array<T>		Array to compact. truthly values

Return:

Array<T>

Returns the new array of filtered values.

Example:

let dataArray = [0, -3, 'Hello', '', false, true, {}, [], null, undefined];

compact(dataArray, 3); // [-3, 'Hello', true, {}, []]

public compareDecimalNumbers(number1: number, number2: number): boolean source

import {compareDecimalNumbers} from 'js-helpers/src/Math/index.js'

Compares two small decimal values.

Params:

Name	Type	Attribute	Description
number1	number		First number to compare.
number2	number		Second number to compare.

Return:

true if two number are equal.

public compose(fns: ...Function): Function source

import {compose} from 'js-helpers/src/Function/index.js'

This method is like pipe except that it creates a function that invokes the provided functions from right to left.

Params:

Name	Type	Attribute	Description
fns	...Function		Function that should be invoked with given arguments.

Return:

Returns the new function.

public conformsTo(object: object, predicateSetModel: object): boolean source

import {conformsTo} from 'js-helpers/src/Object/index.js'

Checks object properties with set of predicates.

Params:

Name	Type	Attribute	Description
object	object		Object which should be chcked.
predicateSetModel	object		Predicate set model.

Return:

Returns true if all predicates returns true.

Example:

let given = { b: 1, a: 'Hello' };

conformsTo(given, { b: n => n === 1, a: n => n === 'Hello' }); // true

conformsTo(given, { b: n => n === 1, a: n => n === 'NOT-Hello' }); // false

public curry(fn: Function): Function | T source

import {curry} from 'js-helpers/src/Function/index.js'

Creates a function that accepts arguments of func and either invokes func returning its result, if at least arity number of arguments have been provided, or returns a function that accepts the remaining func arguments, and so on. The arity of func may be specified if func.length is not sufficient.

Params:

Name	Type	Attribute	Description
fn	Function		Function for Curring.

Return:

Function | T

Function that should collect arguments.

public deepClone(objectToDeepClone: object): object source

import {deepClone} from 'js-helpers/src/Object/index.js'

Will create an object deep clone.

Params:

Name	Type	Attribute	Description
objectToDeepClone	object		Object that should be deep cloned.

Return:

Clone of passed object.

public deepEquals(first: any, second: any): boolean source

import {deepEquals} from 'js-helpers/src/Object/index.js'

Compares two elements.

Params:

Name	Type	Attribute	Description
first	any		First element for comparation.
second	any		Second element for comparation.

Return:

Returns true if two elements are the same.

Example:

deepEquals(
  [
    { id: 1, firstName: 'Jon', lastName: 'Snow', age: 14, location: 'Winterfell' },
    { id: 2, firstName: 'Eddard', lastName: 'Stark', age: 35, location: 'Winterfell' },
    { id: 3, firstName: 'Catelyn', lastName: 'Stark', age: 33, location: 'Winterfell' },
    { id: 4, firstName: 'Roose', lastName: 'Bolton', age: 40, location: 'Dreadfort' },
    { id: 5, firstName: 'Ramsay', lastName: 'Snow', age: 15, location: 'Dreadfort' }
  ],
  [
    { id: 1, firstName: 'Jon', lastName: 'Snow', age: 14, location: 'Winterfell' },
    { id: 2, firstName: 'Eddard', lastName: 'Stark', age: 35, location: 'Winterfell' },
    { id: 3, firstName: 'Catelyn', lastName: 'Stark', age: 33, location: 'Winterfell' },
    { id: 4, firstName: 'Roose', lastName: 'Bolton', age: 40, location: 'Dreadfort' },
    { id: 5, firstName: 'Ramsay', lastName: 'Snow', age: 15, location: 'Dreadfort' }
  ]
); // true

deepEquals(
  [
    { id: 1, firstName: 'Jon', lastName: 'Snow', age: 14, location: 'Winterfell' },
    { id: 2, firstName: 'Eddard', lastName: 'Stark', age: 35, location: 'Winterfell' },
    { id: 3, firstName: 'Catelyn', lastName: 'Stark', age: 33, location: 'Winterfell' },
    { id: 4, firstName: 'Roose', lastName: 'Bolton', age: 40, location: 'Dreadfort' },
    { id: 5, firstName: 'Ramsay', lastName: 'Snow', age: 15, location: 'Dreadfort' }
  ],
  [
    { id: 1, firstName: 'Jon', lastName: 'Snow', age: 14, location: 'Winterfell' },
    { id: 2, firstName: 'Eddard', lastName: 'Stark', age: 35, location: 'Winterfell' },
    { id: 3, firstName: 'Catelyn', lastName: 'Stark', age: 33, location: 'Winterfell' },
    { id: 4, firstName: 'Roose', lastName: 'Bolton', age: 40, location: 'Dreadfort' },
    { id: 5, firstName: 'Not the same!', lastName: 'Snow', age: 15, location: 'Dreadfort' }
  ]
); // false

public deepFreeze(obj: object): object source

import {deepFreeze} from 'js-helpers/src/Object/index.js'

Will deep frezee all properties.

Params:

Name	Type	Attribute	Description
obj	object		Object that should be fully freezed.

Return:

Freezed object.

public divide(dividend: number, divisorList: number): number source

import {divide} from 'js-helpers/src/Math/index.js'

Divide numbers.

Params:

Name	Type	Attribute	Description
dividend	number		The first number in a division.
divisorList	number		The divisor list.

Return:

Returns the quotient.

public duplication(fn: Function): Function source

import {duplication} from 'js-helpers/src/Function-Combinators/index.js'

Takes function and invokes it with passed argument two times.

Params:

Name	Type	Attribute	Description
fn	Function		Function which will be invoked two times with the same argument.

Return:

Function which expects for argument.

Example:

const add = x => y => x + y;

duplication(add)(7); // 14

public eq(elem1: T): Function source

import {eq} from 'js-helpers/src/Predicate/index.js'

Checks if two elements are the same

Params:

Name	Type	Attribute	Description
elem1	T		Element which will be compared with other.

Return:

Function which take second element for comparation.

Example:

eq(1)(1) // true
eq(1)(2) // false

eq('hello')('hello') // true
eq('hello')('hello2') // false

eq({ greeting: 'hello' })({ greeting: 'hello' }) // false

public equalsIgnoreCase(str1: String, str2: String): boolean source

import {equalsIgnoreCase} from 'js-helpers/src/String/index.js'

Will compare two strings with ignore case.

Params:

Name	Type	Attribute	Description
str1	String		First string to compare.
str2	String		Second string to compare.

Return:

Result of comparison.

public every(source: Array<T>, fn: Function): boolean source

import {every} from 'js-helpers/src/Array/index.js'

Checks if predicate returns truthy for all elements of collection. Iteration is stopped once predicate returns falsey.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	Array to check.
fn	Function		Predicate function.

Return:

true if all items will be returned by predicate function.

public fill(source: T, number: number): Array<T> source

import {fill} from 'js-helpers/src/Array/index.js'

Will fill array by given value.

Params:

Name	Type	Attribute	Description
source	T		Fill value.
number	number		Number of filled elements in Array.

Return:

Array<T>

Array with n elements filled by T.

public fillLeft(value: T, number: number, source: Array<T|D>): Array<T|D> source

import {fillLeft} from 'js-helpers/src/Array/index.js'

Will fill array in the begining for n elements and add given array in the end.

Params:

Name	Type	Attribute	Description
value	T		Fill Value.
number	number		Number of elements that should be filled in the begining of returned an array.
source	Array<T\|D>	optional default: []	Fill Value.

Return:

Array<T|D>

Returns combination from given and filled array.

public fillRight(value: T, number: number, source: Array<T|D>): Array<T|D> source

import {fillRight} from 'js-helpers/src/Array/index.js'

Will fill array in the end for n elements and add given array from begining.

Params:

Name	Type	Attribute	Description
value	T		Fill Value.
number	number		Number of elements that should be filled in the end of returned an array.
source	Array<T\|D>	optional default: []	Fill Value.

Return:

Array<T|D>

Returns combination from given and filled array.

public filter(source: Array<T>, fn: Function): Array<T> source

import {filter} from 'js-helpers/src/Array/index.js'

Will filter an array.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	Array that should use filtered function.
fn	Function		Predicate function.

Return:

Array<T>

Filtered Array.

public find(source: Array<T>, fn: Function): T source

import {find} from 'js-helpers/src/Array/index.js'

Iterates over elements of collection, returning the first element predicate returns truthy for.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	Array where check.
fn	Function		Predicate function.

Return:

T	Item if it was found by function predicate.

public first(source: Array<T>): T source

import {first} from 'js-helpers/src/Array/index.js'

Will return first element from array. Is analog of head(*) function.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	Array where to check for first element.

Return:

T	Returns first element from Array.

public flatten(source: Array<T>): * source

import {flatten} from 'js-helpers/src/Array/index.js'

Flattens array.

Params:

Name	Type	Attribute	Description
source	Array<T>		Array that should be flatten.

Return:

*	Returns the new flattened array.

public flip(fn: Function): Function source

import {flip} from 'js-helpers/src/Function-Combinators/index.js'

Takes function and changes argument order. C - combinator implementation.

Params:

Name	Type	Attribute	Description
fn	Function		Function which will be invoked with fliped arguments.

Return:

Function which expects to get first argument, which will be used as a second argument.

Example:

const concat2Words = w1 => w2 => `${w1} ${w2}`;

flip(concat2Words)('world')('hello'); // 'hello world'

public fork(join: Function, fn1: Function, fn2: Function): Function source

import {fork} from 'js-helpers/src/Function-Combinators/index.js'

The fork combinator is useful in cases where you need to process a single resource in two different ways and then combine the results. This combinator takes three functions: a join function and two terminal functions that process the provided input. The result of each forked function is ultimately passed in to a join function of two arguments.

Params:

Name	Type	Attribute	Description
join	Function		Argument that should returned back from function which was returned.
fn1	Function		First terminal function.
fn2	Function		Second terminal function.

Return:

Returns function which expects to get argument that should be passed into terminal functions.

Example:

const calc = fork(multiply, x => x + x, identity);
calc(2); // 8

public getFirstLowerLetter(source: String): String source

import {getFirstLowerLetter} from 'js-helpers/src/String/index.js'

Will return first lower letter from source.

Params:

Name	Type	Attribute	Description
source	String		Source for searching.

Return:

First lower letter.

public getFirstUpperLetter(source: String): String source

import {getFirstUpperLetter} from 'js-helpers/src/String/index.js'

Will return first upper letter from source.

Params:

Name	Type	Attribute	Description
source	String		Source for searching.

Return:

First capital letter.

public getLastLowerLetter(source: String): String source

import {getLastLowerLetter} from 'js-helpers/src/String/index.js'

Will return last lower letter from source.

Params:

Name	Type	Attribute	Description
source	String		Source for searching.

Return:

Last lower letter.

public getLastUpperLetter(source: String): String source

import {getLastUpperLetter} from 'js-helpers/src/String/index.js'

Will return last upper letter from source.

Params:

Name	Type	Attribute	Description
source	String		Source for searching.

Return:

Last capital letter.

public getRandomInt(max: number): number source

import {getRandomInt} from 'js-helpers/src/Math/index.js'

Will generate random integer.

Params:

Name	Type	Attribute	Description
max	number		Max number that can be returned.

Return:

Random integer.

public getRandomIntFromTo(min: number, max: number): number source

import {getRandomIntFromTo} from 'js-helpers/src/Math/index.js'

Will generate random integer in passed range.

Params:

Name	Type	Attribute	Description
min	number		Min number that can be returned.
max	number		Max number that can be returned.

Return:

Random integer.

public getType(valToCheck: T): string source

import {getType} from 'js-helpers/src/Type/index.js'

Checks type of passed value.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

string

Returns object type.

public getTypeByClass(clazz: T): string source

import {getTypeByClass} from 'js-helpers/src/Type/index.js'

Returns class name.

Params:

Name	Type	Attribute	Description
clazz	T		Source which should be a class.

Return:

string

Name of class.

Example:

getTypeByClass(String); // string
getTypeByClass(RegExp); // regexp
getTypeByClass(Object); // object
getTypeByClass(Function); // function
getTypeByClass(Date); // date
getTypeByClass(Boolean); // boolean
getTypeByClass(Number); // number
getTypeByClass(Array); // array
getTypeByClass(Symbol); // symbol

class Person {}
getTypeByClass(Person); // person

public getWithCtx(obj: object): Function source

import {getWithCtx} from 'js-helpers/src/Object/index.js'

Curry version of get function that expects in future to get property list.

Params:

Name	Type	Attribute	Description
obj	object		Context object.

Return:

Curry functions that expects to get property list.

public getWithProps(props: ...string): Function source

import {getWithProps} from 'js-helpers/src/Object/index.js'

Curry version of get function that expects in future to get context.

Params:

Name	Type	Attribute	Description
props	...string		Property chain.

Return:

Curry functions that expects to get context object.

public groupBy(args: ...any): object source

import {groupBy} from 'js-helpers/src/Array/index.js'

Will group objects in array by given property, function or path.

Params:

Name	Type	Attribute	Description
args	...any		grouping arguments.

Return:

Grouped object.

Example:

let actualObjArr = [
  { name: 'John', age: 21 },
  { name: 'Liza', age: 23 },
  { name: 'John', age: 23 }
];

groupBy(['one', 'two', 'three'], 'length');
// { '3': ['one', 'two'], '5': ['three'] });

groupBy(actualObjArr, 'name');
// {
//   John: [ { name: 'John', age: 21 }, { name: 'John', age: 23 } ],
//   Liza: [ { name: 'Liza', age: 23 } ]
// }

groupBy(actualObjArr, 'age');
// {
//   '21': [ { name: 'John', age: 21 } ],
//   '23': [ { name: 'Liza', age: 23 }, { name: 'John', age: 23 } ]
// };

groupBy([6.1, 4.2, 6.3], Math.floor)
// { '4': [4.2], '6': [6.1, 6.3] }

groupBy([
  { name: 'John', age: 21 },
  { name: 'Liza', age: 23 },
  { name: 'John', age: 23 }
], item => `name_${item.name}`);
// {
//   name_John: [ { name: 'John', age: 21 }, { name: 'John', age: 23 } ],
//   name_Liza: [ { name: 'Liza', age: 23 } ]
// }

groupBy([
  { name: { first: 'John', last: 'aaa' }, age: 21 },
  { name: { first: 'Liza', last: 'bbb'}, age: 23 },
  { name: { first: 'John', last: 'ccc'}, age: 23 } ], ['name', 'first']);
// {
//   John: [
//     { name: { first: 'John', last: 'aaa' }, age:21 },
//     { name: { first: 'John', last: 'ccc' }, age:23 }
//   ],
//   Liza: [
//     { name :{ first: 'Liza', last: 'bbb' }, age: 23 }
//   ]
// }

public groupByFn(source: Array<object>, groupFn: Function): object source

import {groupByFn} from 'js-helpers/src/Array/index.js'

Will group objects in array by function.

Params:

Name	Type	Attribute	Description
source	Array<object>		Source which should be used for grouping.
groupFn	Function		Function which will define names for groups.

Return:

Grouped object.

Example:

groupByFn([6.1, 4.2, 6.3], Math.floor)
// { '4': [4.2], '6': [6.1, 6.3] }

groupByFn([
  { name: 'John', age: 21 },
  { name: 'Liza', age: 23 },
  { name: 'John', age: 23 }
], item => `name_${item.name}`);
// {
//   name_John: [ { name: 'John', age: 21 }, { name: 'John', age: 23 } ],
//   name_Liza: [ { name: 'Liza', age: 23 } ]
// }

public groupByPath(source: Array<object>, groupPath: *): object source

import {groupByPath} from 'js-helpers/src/Array/index.js'

Will group objects in array by object path.

Params:

Name	Type	Attribute	Description
source	Array<object>		Source which should be used for grouping.
groupPath	*		Path which should be used as name for groups.

Return:

Grouped object.

Example:

groupByPath([
  { name: { first: 'John', last: 'aaa' }, age: 21 },
  { name: { first: 'Liza', last: 'bbb'}, age: 23 },
  { name: { first: 'John', last: 'ccc'}, age: 23 } ], ['name', 'first']);

// {
//   John: [
//     { name: { first: 'John', last: 'aaa' }, age: 21 },
//     { name: { first: 'John', last: 'ccc' }, age: 23 }
//   ],
//   Liza: [
//     { name :{ first: 'Liza', last: 'bbb' }, age: 23 }
//   ]
// }

public groupByProp(source: Array<object>, groupVal: string): object source

import {groupByProp} from 'js-helpers/src/Array/index.js'

Will group objects in array by property.

Params:

Name	Type	Attribute	Description
source	Array<object>		Source which should be used for grouping.
groupVal	string		Name which should be used for grouping.

Return:

Grouped object.

Example:

let actualObjArr = [
  { name: 'John', age: 21 },
  { name: 'Liza', age: 23 },
  { name: 'John', age: 23 }
];

groupBy(['one', 'two', 'three'], 'length');
// { '3': ['one', 'two'], '5': ['three'] }

groupBy(actualObjArr, 'name');
// {
//   John: [ { name: 'John', age: 21 }, { name: 'John', age: 23 } ],
//   Liza: [ { name: 'Liza', age: 23 } ]
// }

groupBy(actualObjArr, 'age');
// {
//   '21': [ { name: 'John', age: 21 } ],
//   '23': [ { name: 'Liza', age: 23 }, { name: 'John', age: 23 } ]
// };

public gt(number1: number): Function source

import {gt} from 'js-helpers/src/Predicate/index.js'

Saves number1 and returns predicate function that will be checking if number2 is greater then number1.

Params:

Name	Type	Attribute	Description
number1	number		First number.

Return:

Predicate Function.

public gte(number1: number): Function source

import {gte} from 'js-helpers/src/Predicate/index.js'

Saves number1 and returns predicate function that will be checking if number2 is greater then or equal to number1.

Params:

Name	Type	Attribute	Description
number1	number		First number.

Return:

Predicate Function.

public head(source: Array<T>): T source

import {head} from 'js-helpers/src/Array/index.js'

Will return first element from array. Is analog of first(*) function.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	Array where to check for first element.

Return:

T	Returns first element from Array.

public identity(value: T): T source

import {identity} from 'js-helpers/src/Function-Combinators/index.js'

The identity combinator is a function that returns the same value it was provided as an argument. I - combinator implementation.

Params:

Name	Type	Attribute	Description
value	T		Argument that should returned back.

Return:

T	Returns same value which was passed.

Example:

identity(2); // 2

public includes(source: String, includement: String | number): boolean source

import {includes} from 'js-helpers/src/String/index.js'

Work similary to indexOf method but returns boolean.

Params:

Name	Type	Attribute	Description
source	String		String source.
includement	String \| number		Searching value.

Return:

Result of searching as boolean.

public invoke(fns: ...Function): object source

import {invoke} from 'js-helpers/src/Context/index.js'

Will invoke list of functions with given context.

Params:

Name	Type	Attribute	Description
fns	...Function		List of functions that should be invoked with given context.

Return:

object that will have a using(*) function. In using function should be passed context object.

public invokeWithCtx(ctx: object, fns: ...Function): void source

import {invokeWithCtx} from 'js-helpers/src/Context/index.js'

Will invoke list of functions with given context in single invokation.

Params:

Name	Type	Attribute	Description
ctx	object		Contecxt for all functions that should be invoked.
fns	...Function		List of functions that should be invoked with given context.

Return:

void

public isArray(valToCheck: T): boolean source

import {isArray} from 'js-helpers/src/Type/index.js'

Checks if passed value is Array.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is Array.

public isBoolean(valToCheck: T): boolean source

import {isBoolean} from 'js-helpers/src/Type/index.js'

Checks if passed value is boolean.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is boolean.

public isDate(valToCheck: T): boolean source

import {isDate} from 'js-helpers/src/Type/index.js'

Checks if passed value is Date.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is Date.

public isFunction(valToCheck: T): boolean source

import {isFunction} from 'js-helpers/src/Type/index.js'

Checks if passed value is Function.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is Function.

public isNaN(valToCheck: T): boolean source

import {isNaN} from 'js-helpers/src/Type/index.js'

Checks if passed value is NaN.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is NaN.

public isNegativeZero(numberToCheck: number): boolean source

import {isNegativeZero} from 'js-helpers/src/Type/index.js'

Checks if passed value is negative zero.

Params:

Name	Type	Attribute	Description
numberToCheck	number		Value to Check.

Return:

Returns true is passed value is negative zero.

public isNotArray(valToCheck: T): boolean source

import {isNotArray} from 'js-helpers/src/Type/index.js'

Checks if passed value is not Array.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not Array.

public isNotBoolean(valToCheck: T): boolean source

import {isNotBoolean} from 'js-helpers/src/Type/index.js'

Checks if passed value is not boolean.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not boolean.

public isNotDate(valToCheck: T): boolean source

import {isNotDate} from 'js-helpers/src/Type/index.js'

Checks if passed value is not Date.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not Date.

public isNotFunction(valToCheck: T): boolean source

import {isNotFunction} from 'js-helpers/src/Type/index.js'

Checks if passed value is not Function.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not Function.

public isNotNaN(valToCheck: T): boolean source

import {isNotNaN} from 'js-helpers/src/Type/index.js'

Checks if passed value is not NaN.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not NaN.

public isNotNegativeZero(numberToCheck: number): boolean source

import {isNotNegativeZero} from 'js-helpers/src/Type/index.js'

Checks if passed value is not negative zero.

Params:

Name	Type	Attribute	Description
numberToCheck	number		Value to Check.

Return:

Returns true is passed value is not negative zero.

public isNotNull(valToCheck: T): boolean source

import {isNotNull} from 'js-helpers/src/Type/index.js'

Checks if passed value is not null.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not null.

public isNotNumber(valToCheck: T): boolean source

import {isNotNumber} from 'js-helpers/src/Type/index.js'

Checks if passed value is not number.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not number.

public isNotObject(valToCheck: T): boolean source

import {isNotObject} from 'js-helpers/src/Type/index.js'

Checks if passed value is not Object.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not Object.

public isNotPrimitive(value: T): boolean source

import {isNotPrimitive} from 'js-helpers/src/Type/index.js'

Determine whether a value is not a primitive type.

Params:

Name	Type	Attribute	Description
value	T		Value to Check.

Return:

Returns true is passed value is not primitive type.

public isNotRegExp(valToCheck: T): boolean source

import {isNotRegExp} from 'js-helpers/src/Type/index.js'

Checks if passed value is not RegExp.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not RegExp.

public isNotString(valToCheck: T): boolean source

import {isNotString} from 'js-helpers/src/Type/index.js'

Checks if passed value is not string.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not string.

public isNotSymbol(valToCheck: T): boolean source

import {isNotSymbol} from 'js-helpers/src/Type/index.js'

Checks if passed value is not Symbol.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not Symbol.

public isNotUndefined(valToCheck: T): boolean source

import {isNotUndefined} from 'js-helpers/src/Type/index.js'

Checks if passed value is not undefined.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is not undefined.

public isNull(valToCheck: T): boolean source

import {isNull} from 'js-helpers/src/Type/index.js'

Checks if passed value is null.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is null.

public isNumber(valToCheck: T): boolean source

import {isNumber} from 'js-helpers/src/Type/index.js'

Checks if passed value is number.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is number.

public isObject(valToCheck: T): boolean source

import {isObject} from 'js-helpers/src/Type/index.js'

Checks if passed value is Object.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is Object.

public isPrimitive(value: T): boolean source

import {isPrimitive} from 'js-helpers/src/Type/index.js'

Determine whether a value is a primitive type.

Params:

Name	Type	Attribute	Description
value	T		Value to Check.

Return:

Returns true is passed value is primitive type.

public isRegExp(valToCheck: T): boolean source

import {isRegExp} from 'js-helpers/src/Type/index.js'

Checks if passed value is RegExp.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is RegExp.

public isSetoid(obj: object): boolean source

import {isSetoid} from 'js-helpers/src/Fantasy-Land/setoid.js'

Checks if passed object implements setoid.

Params:

Name	Type	Attribute	Description
obj	object		Object to check.

Return:

true in case is passed object implements Setoid.

Example:

const comparePeopleFn = (p, p2) => p.id === p2.id;
const PersonSetoid = toSetoid(comparePeopleFn);
const person1 = { id: 1, name: 'Oleh' }
const person2 = {
   id: 2,
   name: 'Oleh',
   equals: p => true
};

isSetoid(PersonSetoid(person1)); // true
isSetoid(person1); // false
isSetoid(person2); // false

public isString(valToCheck: T): boolean source

import {isString} from 'js-helpers/src/Type/index.js'

Checks if passed value is string.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is string.

public isSymbol(valToCheck: T): boolean source

import {isSymbol} from 'js-helpers/src/Type/index.js'

Checks if passed value is Symbol.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is Symbol.

public isUndefined(valToCheck: T): boolean source

import {isUndefined} from 'js-helpers/src/Type/index.js'

Checks if passed value is undefined.

Params:

Name	Type	Attribute	Description
valToCheck	T		Value to Check.

Return:

Returns true is passed value is undefined.

public kebabCase(str: String): String source

import {kebabCase} from 'js-helpers/src/String/index.js'

Converts string to kebab case.

Params:

Name	Type	Attribute	Description
str	String		The string to convert.

Return:

Returns the kebab cased string.

public last(source: Array<T>): T source

import {last} from 'js-helpers/src/Array/index.js'

Will return last element from array. Is analog of tail(*) function.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	Array where to check for last element.

Return:

T	Returns last element from Array.

public lensIndex(index: number, source: Array<T>): T source

import {lensIndex} from 'js-helpers/src/Lens/index.js'

Returns value taken by index from source.

Params:

Name	Type	Attribute	Description
index	number		Index which should be taken within source.
source	Array<T>		Array is source from where should be taken value by index.

Return:

T	value by index.

public lensProp(propName: string): Function source

import {lensProp} from 'js-helpers/src/Lens/index.js'

Returns a lens whose focus is the specified property.

Params:

Name	Type	Attribute	Description
propName	string		Property name which should be taken within source.

Return:

function which expects object to be source.

public lt(number1: number): Function source

import {lt} from 'js-helpers/src/Predicate/index.js'

Saves number1 and returns predicate function that will be checking if number2 is less then number1.

Params:

Name	Type	Attribute	Description
number1	number		First number.

Return:

Predicate Function.

public lte(number1: number): Function source

import {lte} from 'js-helpers/src/Predicate/index.js'

Saves number1 and returns predicate function that will be checking if number2 is less then or equal to number1.

Params:

Name	Type	Attribute	Description
number1	number		First number.

Return:

Predicate Function.

public map(source: Array<T>, fn: Function): Array<D> source

import {map} from 'js-helpers/src/Array/index.js'

Will project array object.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional	Array that should use projection function.
fn	Function		Projection function.

Return:

Array<D>

Projection Array.

public memoize(fn: Function): Function source

import {memoize} from 'js-helpers/src/Function/index.js'

Creates a function that memoizes the result of fn. If resolver is provided, it determines the cache key for storing the result based on the arguments provided to the memoized function. By default, the first argument provided to the memoized function is used as the map cache key.

Params:

Name	Type	Attribute	Description
fn	Function		Function to memoize.

Return:

Memoized function.

public multiply(multiplier: number, multiplicandList: number): number source

import {multiply} from 'js-helpers/src/Math/index.js'

Multiply numbers.

Params:

Name	Type	Attribute	Description
multiplier	number		The first number in a multiplication.
multiplicandList	number		The multiplicand list.

Return:

Returns the product.

public not(predicates: ...Function): Function source

import {not} from 'js-helpers/src/Predicate-Combinator/index.js'

Takes list of predicates and returns a one predicate, current predicate will return true only in case if all passed predicates return false.

Params:

Name	Type	Attribute	Description
predicates	...Function		List of predicates.

Return:

Predicate function.

public notEq(elem1: T): Function source

import {notEq} from 'js-helpers/src/Predicate/index.js'

Checks if two elements are not the same.

Params:

Name	Type	Attribute	Description
elem1	T		Element which will be compared with other.

Return:

Function which take second element for comparation.

Example:

eq(1)(1) // false
eq(1)(2) // true

eq('hello')('hello') // false
eq('hello')('hello2') // true

eq({ greeting: 'hello' })({ greeting: 'hello' }) // true

public notOr(predicates: ...Function): Function source

import {notOr} from 'js-helpers/src/Predicate-Combinator/index.js'

Takes list of predicates and returns a one predicate, current predicate will return true only in the case if none of passed prdicates returns true.

Params:

Name	Type	Attribute	Description
predicates	...Function		List of predicates.

Return:

Predicate function.

public notToBe(expectation: T): Function source

import {notToBe} from 'js-helpers/src/Type/index.js'

Takes expectation and returns predicate function which will be checking if new passed variable not equal to expectation.

Params:

Name	Type	Attribute	Description
expectation	T		Not expected value.

Return:

Returns predicate function.

public nth(source: Array<T>, index: number): T source

import {nth} from 'js-helpers/src/Array/index.js'

Will return element from array by given index.

Params:

Name	Type	Attribute	Description
source	Array<T>		Source where should be taken element by given index.
index	number		Index of element which should be returned.

Return:

T	Returns nth element from Array.

Example:

nth([51,35,23], 1) // 35

public numAndStrComparator(first: string | number, second: string | number, prop: string): number source

import {numAndStrComparator} from 'js-helpers/src/Array/index.js'

number or string comparator. Can be used in sort function.

Params:

Name	Type	Attribute	Description
first	string \| number		First argumnet for comparation.
second	string \| number		Second argumnet for comparation.
prop	string		Compare property.

Return:

Comparation result.

Example:

let given = [
  { 'name': 'fred',   'age': 48 },
  { 'name': 'barney', 'age': 36 }
];

numAndStrComparator(given[0], given[1], 'name'); // 1
numAndStrComparator(given[1], given[0],'name'); // -1
numAndStrComparator(given[0], given[1],'age'); // 1
numAndStrComparator(given[1], given[0],'age'); // -1

public objectProjection(obj: object, cb: Function, skipCb: Function): Array<any> source

import {objectProjection} from 'js-helpers/src/Object/index.js'

Iterates by object properties.

Params:

Name	Type	Attribute	Description
obj	object		Context object.
cb	Function		Callback function which will be invoked with key and value argument.
skipCb	Function		Skip function which allows to skip property by given condition.

Return:

Array<any>

Returns array projected by Callback function.

public omit(source: object, omitArray: ...string): object source

import {omit} from 'js-helpers/src/Object/index.js'

Will create and return a new object with omited properties from omitArray.

Params:

Name	Type	Attribute	Description
source	object		Object that should have updated structure.
omitArray	...string		Properties that should omited in result object.

Return:

Object with excluded properties from omitArray.

public once(fn: Function): T | undefined source

import {once} from 'js-helpers/src/Function/index.js'

Creates a function that is restricted to invoking func once. Repeat calls to the function return undefined.

Params:

Name	Type	Attribute	Description
fn	Function		Function that should be invoked only once.

Return:

T | undefined

Returns invocation result of passed function.

public or(predicates: ...Function): Function source

import {or} from 'js-helpers/src/Predicate-Combinator/index.js'

Takes list of predicates and returns a one predicate, current predicate will return true if at least one of passed predicates returns true.

Params:

Name	Type	Attribute	Description
predicates	...Function		List of predicates.

Return:

Predicate function.

public orCurry(fn: Function, args: ArrayLike | Array<any>): Function | T source

import {orCurry} from 'js-helpers/src/Function/index.js'

Creates curry variation of function if some of arguments are missed.

Params:

Name	Type	Attribute	Description
fn	Function		Function for Curring.
args	ArrayLike \| Array<any>		Arguments which should be invoked woith passed function.

Return:

Function | T

Function that should collect arguments or result on invokation.

public partial(fn: Function, partialArgs: ...T): Function source

import {partial} from 'js-helpers/src/Function/index.js'

Creates a function that invokes fn with partials prepended to the arguments it receives.

Params:

Name	Type	Attribute	Description
fn	Function		The function to partially apply arguments to.
partialArgs	...T		Arguments that should be applied.

Return:

Returns the new partially applied function.

public path(p: Array<string>, source: object): any source

import {path} from 'js-helpers/src/Lens/index.js'

Retrieve the value at a given path.

Params:

Name	Type	Attribute	Description
p	Array<string>		Path to value.
source	object		Source to use.

Return:

any	Value by path.

public pathEq(path: Array<string>, source: object, value: any): any source

import {pathEq} from 'js-helpers/src/Lens/index.js'

Retrieve the value at a given path and compares it with given value.

Params:

Name	Type	Attribute	Description
path	Array<string>		Path to value.
source	object		Source to use.
value	any		Value for comparing.

Return:

any	Comparation result.

public pathOr(path: Array<string>, source: object, orValue: any): any source

import {pathOr} from 'js-helpers/src/Lens/index.js'

Retrieve the value at a given path and if value is undefined returns orValue.

Params:

Name	Type	Attribute	Description
path	Array<string>		Path to value.
source	object		Source to use.
orValue	any		Value which should be returned in case if path doesn't exist.

Return:

any	Value by path or orValue.

public pathSatisfies(path: Array<string>, source: object, satisfyFn: Function): any source

import {pathSatisfies} from 'js-helpers/src/Lens/index.js'

Retrieve the value at a given path and returns result of invocation satisfy function with value by path.

Params:

Name	Type	Attribute	Description
path	Array<string>		Path to value.
source	object		Source to use.
satisfyFn	Function		Function which will be invoked with path value.

Return:

any	Result of invocation satisfy function with value by path.

public pick(source: object, pickArray: ...string): object source

import {pick} from 'js-helpers/src/Object/index.js'

Will create and return a new object with selected properties from pickArray.

Params:

Name	Type	Attribute	Description
source	object		Object that should have updated structure.
pickArray	...string		Properties that should be included in result object.

Return:

Object that includes pickArray property list.

public pipe(fns: ...Function): Function source

import {pipe} from 'js-helpers/src/Function/index.js'

Creates a function that returns the result of invoking the provided f unctions with the this binding of the created function, where each successive invocation is supplied the return value of the previous.

Params:

Name	Type	Attribute	Description
fns	...Function		Function that should be invoked with given arguments.

Return:

Returns the new function.

public pluck(source: Array<Object>, propName: string): Array<T> source

import {pluck} from 'js-helpers/src/Array/index.js'

Will return array of selected properties.

Params:

Name	Type	Attribute	Description
source	Array<Object>	optional default: []	Array for propjection.
propName	string		Name of the property from that should be included in Array.

Return:

Array<T>

Packed array of selected properties.

public prop(propName: string, source: object): T source

import {prop} from 'js-helpers/src/Lens/index.js'

Returns value taken by property from source.

Params:

Name	Type	Attribute	Description
propName	string		Property name which should be taken within source.
source	object		Object is source from where should be taken value by property name.

Return:

T	property value.

Example:

let user = { name: { first: 'Oleh' } };
eq({ first: 'Oleh' }, prop('name', user)); // false
eq(prop('name', user).first, 'Oleh'); // true

public range(number1: number, number2: number): Function source

import {range} from 'js-helpers/src/Predicate/index.js'

Saves number1, number2 and returns predicate function that will be checking if future passed number is in range of number1 and number2.

Params:

Name	Type	Attribute	Description
number1	number		Min range number.
number2	number		Max range number.

Return:

Predicate Function.

public rangeEqual(number1: number, number2: number): Function source

import {rangeEqual} from 'js-helpers/src/Predicate/index.js'

Saves number1, number2 and returns predicate function that will be checking if future passed number is in range of number1 and number2 or equal to number1/number2.

Params:

Name	Type	Attribute	Description
number1	number		Min range number.
number2	number		Max range number.

Return:

Predicate Function.

public rearg(fn: Function, order: Array<number>): * source

import {rearg} from 'js-helpers/src/Function/index.js'

Reorginizes argument order.

Params:

Name	Type	Attribute	Description
fn	Function		Function that should be invoked with reorganized argument order.
order	Array<number>		Argument order.

Return:

public reject(source: Array<T>, fn: Function): Array<T> source

import {reject} from 'js-helpers/src/Array/index.js'

The opposite of filter; this method returns the elements of collection that predicate does not return truthy for.

Params:

Name	Type	Attribute	Description
source	Array<T>		Array that should checked.
fn	Function		Opposite filter function.

Return:

Array<T>

Returns the new filtered array.

Example:

 let numberArray = [1, 2, 3]
   , objectArray = [{ name: 'John' }, { name: 'Liza' }];

 reject(numberArray, item => item < 3) // [3]
 reject(objectArray, user => user.name === 'Liza') // [{ name: 'John' }]

public replaceAll(replaceable: String, from: String, to: T): String source

import {replaceAll} from 'js-helpers/src/String/index.js'

Will replace all occurrences.

Params:

Name	Type	Attribute	Description
replaceable	String		Source for replacements.
from	String		Property that should be replaced.
to	T		Proprty that should be included instead of `from` propperty.

Return:

New String with all replacements.

public replaceAllDifferences(replaceable: String, fromList: Array<T>, to: Array<T>): String source

import {replaceAllDifferences} from 'js-helpers/src/String/index.js'

Will replace all different occurrences.

Params:

Name	Type	Attribute	Description
replaceable	String		Source for replacements.
fromList	Array<T>		Array of properties that should be replaced.
to	Array<T>		Array of properties that should be injected to source.

Return:

New String with all replacements.

public safeGet(obj: object, props: ...string): * source

import {safeGet} from 'js-helpers/src/Object/index.js'

Implementation of optional chain operator.

Params:

Name	Type	Attribute	Description
obj	object		Context object.
props	...string		Property chain.

Return:

*	Context value by property chain.

public safeGetOr(obj: object, orValue: any, props: ...string): any source

import {safeGetOr} from 'js-helpers/src/Object/index.js'

Implementation of optional chain operator.

Params:

Name	Type	Attribute	Description
obj	object		Context object.
orValue	any		Value which will be returned if obj doesn't contain truthly value.
props	...string		Property chain.

Return:

any	Context value by property chain or orValue.

public sample(source: Array<T>): T source

import {sample} from 'js-helpers/src/Array/index.js'

Will return random element from array.

Params:

Name	Type	Attribute	Description
source	Array<T>		Array from where should be choosen random element.

Return:

T	Random element.

public seq(fns: ...Function): Function source

import {seq} from 'js-helpers/src/Function-Combinators/index.js'

The seq combinator is used to loop over a sequence of functions.

Params:

Name	Type	Attribute	Description
fns	...Function		List of functions which will be invoked sequently.

Return:

Returns a new function, which runs all of them in sequence against the same value.

Example:

let result = 0
  , addToResult = x => result += x;

result; // 0

seq(addToResult, addToResult)(4);

result; // 8

public shuffle(source: Array<T>): Array<T> source

import {shuffle} from 'js-helpers/src/Array/index.js'

Will shuffle elements in array.

Params:

Name	Type	Attribute	Description
source	Array<T>		Array to shuffle.

Return:

Array<T>

Array that is shuffled out.

Example:

shuffle([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
// [ 1, 5, 3, 4, 2, 6, 10, 7, 8, 9 ]

shuffle([
  { name: 'name1' },
  { name: 'name2' },
  { name: 'name3' },
  { name: 'name4' },
  { name: 'name5' },
  { name: 'name6' },
  { name: 'name7' },
  { name: 'name8' },
  { name: 'name9' },
  { name: 'name10' }
]);
// [
//   { name: 'name2' },
//   { name: 'name3' },
//   { name: 'name4' },
//   { name: 'name1' },
//   { name: 'name9' },
//   { name: 'name6' },
//   { name: 'name8' },
//   { name: 'name7' },
//   { name: 'name10' },
//   { name: 'name5' }
// ]

public snakeCase(str: String): String source

import {snakeCase} from 'js-helpers/src/String/index.js'

Converts string to snake case.

Params:

Name	Type	Attribute	Description
str	String		The string to convert.

Return:

Returns the snake cased string.

public some(source: Array<T>, fn: Function): boolean source

import {some} from 'js-helpers/src/Array/index.js'

Checks if predicate returns truthy for any element of collection. Iteration is stopped once predicate returns truthy. Is analog of any(*) function.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	The collection to iterate over.
fn	Function		The collection to iterate over.

Return:

Returns true if any element passes the predicate check, else false.

public sortBy(source: Array<object>, propList: Array<string>): Array<object> source

import {sortBy} from 'js-helpers/src/Array/index.js'

Sorts array of objects by given properties with priorities.

Params:

Name	Type	Attribute	Description
source	Array<object>		Source which requires sorting.
propList	Array<string>		Sorting property list.

Return:

Array<object>

Sorted array of objects.

Example:

 let given = [
   { 'name': 'fred',   'age': 48 },
   { 'name': 'barney', 'age': 36 },
   { 'name': 'fred',   'age': 32 },
   { 'name': 'barney', 'age': 34 }
 ];

 sortBy(given, ['name', 'age']);
 //  [
 //    { name: 'barney', age: 34 },
 //    { name: 'barney', age: 36 },
 //    { name: 'fred', age: 32 },
 //    { name: 'fred', age: 48 }
 //  ]

public subtract(minuend: number, subtrahendList: number): number source

import {subtract} from 'js-helpers/src/Math/index.js'

Subtract numbers.

Params:

Name	Type	Attribute	Description
minuend	number		The first number in a subtraction.
subtrahendList	number		The subtrahend list.

Return:

Returns the difference.

public tail(source: Array<T>): T source

import {tail} from 'js-helpers/src/Array/index.js'

Will return last element from array. Is analog of last(*) function.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	Array where to check for last element.

Return:

T	Returns last element from Array.

public take(source: Array<T>, sourceLength: number): Array<T> source

import {take} from 'js-helpers/src/Array/index.js'

Will return first n elements.

Params:

Name	Type	Attribute	Description
source	Array<T>		Array to slice.
sourceLength	number	optional default: 1	Number of first n elements that should be returned back.

Return:

Array<T>

First n elements from Array.

Example:

let numberArray = [1, 2, 3]
  , objectArray = [{ name: 'John' }, { name: 'Liza' }];

take(numberArray); // [1]
take(objectArray); // [{ name: 'John' }]

take(numberArray, 2); // [1, 2]
take(objectArray, 2); // [{ name: 'John' }, { name: 'Liza' }]

public takeRight(source: Array<T>, numberOfLastElements: number): Array<T> source

import {takeRight} from 'js-helpers/src/Array/index.js'

Will return last n elements from an array.

Params:

Name	Type	Attribute	Description
source	Array<T>		Array to slice.
numberOfLastElements	number	optional default: 1	Number of last n elements that should be returned back.

Return:

Array<T>

Last n elements from Array.

public takeRightWhile(source: Array<T>, rightWhileFn: Function): Array<T> source

import {takeRightWhile} from 'js-helpers/src/Array/index.js'

Creates a slice of array with elements taken from the end. Elements are taken until predicate returns falsey.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	The array to query.
rightWhileFn	Function		The function invoked per iteration.

Return:

Array<T>

Last n elements from Array before match.

public takeWhile(source: Array<T>, whileFn: Function): Array<T> source

import {takeWhile} from 'js-helpers/src/Array/index.js'

Creates a slice of array with elements taken from the beginning. Elements are taken until predicate returns falsey.

Params:

Name	Type	Attribute	Description
source	Array<T>	optional default: []	The array to query.
whileFn	Function		The function invoked per iteration.

Return:

Array<T>

First n elements from Array before match.

public tap(fn: Function): Function source

import {tap} from 'js-helpers/src/Function-Combinators/index.js'

Helps to check data in chain. Useful for debugging.

Params:

Name	Type	Attribute	Description
fn	Function		Middleware function.

Return:

Returns data that was used for tap functio

Example:

let sayHelloTo = name => `Hello ${name}`
  , toUpperCase = str => str.toUpperCase()
  , addDollarSign  = str => `$${str}$`
  , chainMiddleResult = ''
  , tapHandler = data => chainMiddleResult = data
  , sayHelloInUpperCase = compose(addDollarSign, sayHelloTo, tap(tapHandler), toUpperCase);

 sayHelloInUpperCase('oleh'); // '$Hello OLEH$'
 chainMiddleResult; // 'OLEH'

public throwIncorrectArgsTypeErrorIfSomeOf(conditions: ...boolean) source

import {throwIncorrectArgsTypeErrorIfSomeOf} from 'js-helpers/src/Error/index.js'

Throws IncorrectArgsTypeError if at least one of conditions is positive.

Params:

Name	Type	Attribute	Description
conditions	...boolean		Conditions which should be negative in order to not throw IncorrectArgsTypeError error.

Throw:

IncorrectArgsTypeError

throw error when one of conditions is true.

public thrush(x: any): Function source

import {thrush} from 'js-helpers/src/Function-Combinators/index.js'

Takes argument and returns function which expects to get function which will be invoked with first argument. T - combinator implementation.

Params:

Name	Type	Attribute	Description
x	any		Argument which will be passed into a function which is expected as a second argument.

Return:

Function which expects to get function where will be passed first argument.

Example:

const addWorld = w => `${w} world`;

thrush('hello')(addWorld); // 'hello world'

public times(iterationNumber: number, fn: Function): Array<T> source

import {times} from 'js-helpers/src/Array/index.js'

Invokes the iteratee n times, returning an array of the results of each invocation.

Params:

Name	Type	Attribute	Description
iterationNumber	number		Number of iterations.
fn	Function		Function that should be invoked with each iteration.

Return:

Array<T>

Result array.

public toBe(expectation: T): Function source

import {toBe} from 'js-helpers/src/Type/index.js'

Takes expectation and returns predicate function which will be checking if new passed variable equal to expectation.

Params:

Name	Type	Attribute	Description
expectation	T		Expected value.

Return:

Returns predicate function.

public toSetoid(eqFn: Function): Setoid source

import {toSetoid} from 'js-helpers/src/Fantasy-Land/setoid.js'

Creates Setoid from given function.

Params:

Name	Type	Attribute	Description
eqFn	Function		Setoid implementation function.

Return:

Setoid

New concrete Setoid implementation.

Example:

const comparePeopleFn = (p, p2) => p.id === p2.id;
const PersonSetoid = toSetoid(comparePeopleFn);
const person1 = { id: 1, name: 'Oleh' };
const person2 = { id: 1, name: 'Oleh' };
const person3 = { id: 7, name: 'Oleh' };

PersonSetoid(person1).equals(PersonSetoid(person2))); // true
PersonSetoid(person2).equals(PersonSetoid(person1))); // true

PersonSetoid(person1).equals(PersonSetoid(person3))); // false
PersonSetoid(person2).equals(PersonSetoid(person3))); // false

Object.keys(PersonSetoid(person1)); // ['id', 'name'];

public trim(stringSource: String): * source

import {trim} from 'js-helpers/src/String/index.js'

Removes leading and trailing whitespace or specified characters from string.

Params:

Name	Type	Attribute	Description
stringSource	String		The string to trim.

Return:

*	Returns the trimmed string.

public typeCheck(clazz: T, actualType: any): any source

import {typeCheck} from 'js-helpers/src/Type/index.js'

Checks if type is correct and throws error in negative case.

Params:

Name	Type	Attribute	Description
clazz	T		Expected source which should be a class.
actualType	any		Value which should be checked.

Return:

any	actualType if type is correct else throws error.

Throw:

TypeError

If passed actualType has incorrect type.

Example:

typeCheck(String, ''); // ''
typeCheck(RegExp, /ab+c/); // /ab+c/
typeCheck(Object, {}); // {}
typeCheck(Function, () => {}); // () => {}
typeCheck(Date, new Date()); // Sun Nov 04 2018 01:25:43 GMT+0200 (Eastern European Standard Time)
typeCheck(Boolean, true); // true
typeCheck(Number, 333); // 333
typeCheck(Array, []); // []
typeCheck(Symbol, Symbol('desc')); // Symbol('desc')

typeCheck(String, 777); // TypeError
typeCheck(Number, 'hello'); // TypeError
typeCheck(Boolean, {}); // TypeError
...

public unary(fn: Function): Function source

import {unary} from 'js-helpers/src/Function/index.js'

Create funtion that makes same as passed function but newly created function will use only first argument.

Params:

Name	Type	Attribute	Description
fn	Function		Function that should use only one argument.

Return:

Same function that was passed but now it uses only first argument.

public uniq(source: Array<any>): Array<any> source

import {uniq} from 'js-helpers/src/Array/index.js'

returns new array only with uniq elements

Params:

Name	Type	Attribute	Description
source	Array<any>		Source for uniqueness.

Return:

Array<any>

New array only with unique elements.

Example:

uniq(
  [
    { id: 1, firstName: 'Jon', lastName: 'Snow', location: 'Winterfell' },
    { id: 2, firstName: 'Eddard', lastName: 'Stark', location: 'Winterfell' },
    { id: 3, firstName: 'Catelyn', lastName: 'Stark', location: 'Winterfell' },
    { id: 4, firstName: 'Roose', lastName: 'Bolton', location: 'Dreadfort' },
    { id: 4, firstName: 'Roose', lastName: 'Bolton', location: 'Dreadfort' },
    { id: 5, firstName: 'Ramsay', lastName: 'Snow', location: 'Dreadfort' }
  ]);
// [
//   { id: 1, firstName: 'Jon', lastName: 'Snow', location: 'Winterfell' },
//   { id: 2, firstName: 'Eddard', lastName: 'Stark', location: 'Winterfell' },
//   { id: 3, firstName: 'Catelyn', lastName: 'Stark', location: 'Winterfell' },
//   { id: 4, firstName: 'Roose', lastName: 'Bolton', location: 'Dreadfort' },
//   { id: 5, firstName: 'Ramsay', lastName: 'Snow', location: 'Dreadfort' }
// ]

public upperFirst(str: String): String source

import {upperFirst} from 'js-helpers/src/String/index.js'

Will make a capital first letter.

Params:

Name	Type	Attribute	Description
str	String		Source string.

Return:

Source with first capital letter.

public using(ctx: object): object source

import {using} from 'js-helpers/src/Context/index.js'

Is opposite to invoke function.

Params:

Name	Type	Attribute	Description
ctx	object		Context for all functions that should be invoked.

Return: