Functions

add()

adds two numbers

Kind: global function
Example

add(1, 2)
// returns 3

hasOwn()

returns true or false depending if the provided property is present inside the provided object

Kind: global function
Example

hasOwn('a', { a: 1, b: 2 })
// returns true

assign()

assigns properties of one or more source objects onto target object

Kind: global function
Example

assign({ a: 1, b: 2 }, { b: 4, c: 5 })
// returns { a: 1, b: 4, c: 5 }

capitalizeFirstLetter()

capitalizes first letter of string

Kind: global function
Example

capitalizeFirstLetter('hello')
// returns 'Hello'

flatMap()

returns a new array formed by applying a given callback function to each element of the array, and then flattening the result by one level

Kind: global function
Example

const arr = [{ a: [1, 2] }, { a: [3, 4] }, { a: [5, 6] }]
flatMap(el => el.a, arr)
// returns [1, 2, 3, 4, 5, 6]

chain()

takes two arguments: a function and either an array or another function. The function applies the input function to every element of the input array or to the result of calling the input function on the input array. Then, the results are concatenated into a new array and returned.

Kind: global function
Example

chain(n => [n, n], [1, 2, 3])
// returns [1, 1, 2, 2, 3, 3]
const head = list => list[0]
const append = el => list => list.concat(el)
chain(append, head)([1, 2, 3])
// returns [1, 2, 3, 1]

chunk()

chunks provided array to specified size chunks

Kind: global function
Example

chunk([1, 2, 3, 4], 2)
// returns [[1, 2], [3, 4]]

isArray()

determines whether provided value is an array

Kind: global function
Example

isArray([1, 2])
// returns true
isArray('hello')
// returns false

isObject()

returns true or false depending if the provided value is an object

Kind: global function
Example

isObject({ a: 1 })
// returns true
isObject([1, 2])
// returns false

keys()

returns an array of the provided object keys

Kind: global function
Example

keys({ a: 1, b: 2, c: 3 })
// returns ['a', 'b', 'c']

mapValues()

maps values of the provided object

Kind: global function
Example

mapValues(val => val.toUpperCase(), { a: 'foo', b: 'bar' })
// returns { a: 'FOO', b: 'BAR' }

cloneDeep()

returns an exact clone of the provided value with a new reference

Kind: global function
Example

cloneDeep({ a: 1, b: 2 })
// returns { a: 1, b: 2 }

camelCase()

converts provided string to camel case

Kind: global function
Example

camelCase('hello_world')
// returns 'helloWorld'

compact()

removes all nullish and NaN values from the provided object or array

Kind: global function
Example

compact({ a: 1, b: null })
// returns { a: 1 }
compact(['hello', undefined])
// returns ['hello']

compose()

returns a composed value from the provided arguments

Kind: global function
Example

const f3 = (a: string) => `f3(${a})`
const f2 = (a: string) => `f2(${a})`
const f1 = (a: string) => `f1(${a})`
compose(f3, f2, f1)('arg')
// returns 'f3(f2(f1(arg)))'

debounce()

delays the execution of a function until a certain period of time has passed without the function being called again

Kind: global function
Example

debounce(1000, someFunction)

deepMapKeys()

recurses through an object and transforms its keys – and the keys of any nested objects – based on the provided key mapping function

Kind: global function
Example

deepMapKeys(key => `test_${key}`, { a: 1, b: { c: 2 } })
// returns { test_a: 1, test_b: { test_c: 2 } }

deepMerge()

deep merges provided objects by assigning the sources onto the target object passed as the first argument

Kind: global function
Example

deepMerge({ a: 1, b: { c: 2 } }, { b: { d: 3 } })
// returns { a: 1, b: { c: 2, d: 3 } }

isNil()

returns true or false depending if the provided value is null or undefined

Kind: global function
Example

isNil(null)
// returns true

defaultTo()

returns a function that invoked with a null or undefined values returns the provided default

Kind: global function
Example

const defaulter = defaultTo('default')
defaulter('hello')
// returns 'hello'
defaulter(null)
// returns 'default'

diffKeys()

returns an array of keys of the object passed as the first argument that are not present, or that are present, but have different values, in object passed as the second argument

Kind: global function
Example

diffKeys({ a: 1, b: 2, c: 3 }, { c: 3, d: 4 })
// returns ['a', 'b']

drop()

drops specific amount of elements of the provided array starting at the beginning

Kind: global function
Example

drop(2, [1, 2, 3, 4])
// returns [3, 4]

dropRight()

drops specific amount of elements of the provided array starting at the end

Kind: global function
Example

dropRight(2, [1, 2, 3, 4])
// returns [1, 2]

ensureArray()

returns an array if an array was provided, or a new array if provided value was not an array

Kind: global function
Example

ensureArray([1, 2])
// returns [1, 2]
ensureArray('test')
// returns ['test']

entries()

returns an array of entries of the provided object

Kind: global function
Example

entries({ a: 1, b: 2 })
// returns [['a', 1], ['b', 2]]

find()

returns the first element of the provided array that returns true for the predicate function, or undefined if the element was not found

Kind: global function
Example

find(el => el === 2, [1, 2, 3])
// returns 2

findIndex()

returns the index of the element of the provided array that returns true for the predicate function, or -1 if the element was not found

Kind: global function
Example

findIndex(el => el === 2, [1, 2, 3])
// returns 1
findIndex(el => el === 5, [1, 2, 3])
// returns -1

findKey()

returns the key of the provided object that returns true for the predicate function, or undefined if the key was not found

Kind: global function
Example

findKey(el => el === 1, { a: 1, b: { c: 2 } })
// returns 'a'
findKey(el => el === 2, { a: 1, b: { c: 2 } })
// returns undefined

findLast()

returns the last element of the provided array that returns true for the predicate function, or undefined if the element was not found

Kind: global function
Example

findLast(el => el % 2 === 0, [1, 2, 3, 4])
// returns 4

findLastIndexFrom()

returns the index of the last element of the provided array that returns true for the predicate function, starting from the specified index element to the begining of the array, or -1 if the element was not found

Kind: global function
Example

findLastIndexFrom(el => el % 2 === 0, 3, [1, 2, 3, 4, 5, 6])
// returns 3

findLastIndex()

returns the index of the last element of the provided array that returns true for the predicate function, or -1 if the element was not found

Kind: global function
Example

findLastIndex(el => el % 2 === 0, [1, 2, 3, 4])
// returns 3

filledArray()

returns an array of requested length filled with provided value

Kind: global function
Example

filledArray(3, 1)
// returns [1, 1, 1]

identity()

returns the provided value

Kind: global function
Example

identity('hello')
// returns 'hello'

flatten()

flattens the provided array by one level

Kind: global function
Example

flatten([1, 2, [3, 4]])
// returns [1, 2, 3, 4]
flatten([1, 2, [3, [4, 5]], 6])
// returns [1, 2, 3, [4, 5], 6]

forOwn()

invokes the provided callback for each of the provided object fields

Kind: global function
Example

const obj = { a: 1, b: 2, c: 3 }
const arr: string[] = []
forOwn(el => arr.push(el.toString()), obj)
// arr equals ['1', '2', '3']

fromPairs()

returns an object constructed from the provided array of key, value pairs'

Kind: global function
Example

const arr = [
  ['a', 1],
  ['b', 2],
  ['c', 3],
]
fromPairs(arr)
// returns { a: 1, b: 2, c: 3 }

generateRandomId()

generates a random id

Kind: global function
Example

generateRandomId()
// returns 'd1rjknhhch8'

generateUniqueId()

generates an unique id based on the provided object keys

Kind: global function
Example

generateUniqueId({ xuvarw8cao: 1, b837g2nba1d: 2 })
// returns 'd1rjknhhch8'

get()

returns the value from the specififed path from the provided object

Kind: global function
Example

const obj = { a: { b: [1, 2, 3] } }
get('a.b.1', obj)
// returns 2
get(['a', 'b', '1'], obj)
// returns 2

getOr()

returns the value from the specififed path from the provided object or the default value if the path element was not found

Kind: global function
Example

const obj = { a: { b: [1, 2, 3] } }
getOr(null, 'a.b.1', obj)
// returns 2
getOr(null, 'a.c', obj)
// returns null

groupBy()

groups values from the provided array or object based on the result of the provided mapper function

Kind: global function
Example

const arr = [
  { a: 1, b: 2 },
  { a: 2, b: 4 },
  { a: 3, b: 6 },
]
groupBy(el => (el.a % 2 === 0 ? 'even' : 'odd'), arr)
// returns {
// 	odd: [
// 		{ a: 1, b: 2 },
// 		{ a: 3, b: 6 },
// 	],
// 	even: [{ a: 2, b: 4 }],
// }

groupKeys()

groups values from the provided object based on the result of the provided key mapping function

Kind: global function
Example

const obj = { a: 1, b: 2, c: 3 }
groupKeys(el => (el === 'a' ? 'aaa' : 'rest'), obj)
// returns {
//	aaa: { a: 1 },
//	rest: { b: 2, c: 3 },
// }

includes()

returns true or false depending if the provided value is present inside the provided array or string

Kind: global function
Example

includes('a', ['a', 'b', 'c'])
// returns true
includes('d', 'abc')
// returns false

isEmpty()

returns true or false depending if the provided value is an empty object or an empty array

Kind: global function
Example

isEmpty({})
// returns true

isFalsy()

returns true or false depending if the provided value is falsy

Kind: global function
Example

isFalsy(0)
// returns true

isTruthy()

returns true or false depending if the provided value is truthy

Kind: global function
Example

isTruthy(1)
// returns true

isPromise()

returns true or false depending if the provided value is a Promise

Kind: global function
Example

isPromise(new Promise(res => res(null)))
// returns true

keyBy()

constructs an object from the provided array of objects, grouped by the value of the specified key

Kind: global function
Example

const arr = [
  { a: 'foo', b: 'bar' },
  { a: 'foo', b: 'baz' },
  { a: 'test', b: 'bab' },
]
keyBy('a', arr)
// returns { foo: { a: 'foo', b: 'baz' }, test: { a: 'test', b: 'bab' } }

last()

returns the last element of the provided array or undefined when array is empty

Kind: global function
Example

last([1, 2, 3])
// returns 3

mapKeys()

maps keys of the provided object

Kind: global function
Example

mapKeys(key => key.toUpperCase(), { a: 1, b: 2 })
// returns { A: 1, B: 2 }

mapValuesIndexed()

maps values and keys of the provided object

Kind: global function
Example

mapValuesIndexed((val, key) => `${key}-${val}`, { a: 1, b: 2 })
// returns { a: 'a-1', b: 'b-2' }

merge()

deep merges the two provided objects

Kind: global function
Example

merge({ a: 1 }, { b: 2 })
// returns { a: 1, b: 2 }

mergeAll()

deep merges all provided objects

Kind: global function
Example

mergeAll({ a: 1 }, { b: 2 }, { c: 3 })
// returns { a: 1, b: 2, c: 3 }

memoizeWith()

memoizes the provided function so it returns cached results but based on the provided key resolver

Kind: global function
Example

const memoizedFunc = memoizeWith(
  key => (key === 'a' ? key : 'bar'),
  (val: string) => ({ current: val }),
)
memoizedFunc('a') === memoizedFunc('a') // true
memoizedFunc('b') === memoizedFunc('c') // true

memoize()

memoizes the provided function so it returns cached results when invoked with the same arguments

Kind: global function
Example

const memoizedFunc = memoize((val: number) => ({ current: val })
memoizedFunc(3) === memoizedFunc(3)
// returns true

memoizeOne()

memoizes the provided function so it returns cached results but only with one cache key

Kind: global function
Example

const memoizedFunc = memoizeOne((val: number) => ({ current: val })

const resultFor1 = memoizedFunc(1) // { current: 1 }
resultFor1 === memoizedFunc(1) // true
resultFor1 === memoizedFunc(1) // true

const resultFor2 = memoizedFunc(2) // { current: 2 }
resultFor2 === memoizedFunc(2) // true
resultFor1 === memoizedFunc(1) // false

noop()

does literally nothing

Kind: global function
Example

somethingAsyncAndDangerous().catch(noop)

values()

returns an array of values of the provided object

Kind: global function
Example

values({ a: 1, b: 2, c: 3 })
// returns [1, 2, 3]

numericSortBy()

sorts values of the provided object or array based on the provided mapping function or the provided prop string

Kind: global function
Example

const obj = {
  a: { chats: 1 },
  b: { chats: 3 },
  c: { chats: 2 },
}
numericSortBy(el => el.chats * -1, obj)
// returns [{ chats: 3 }, { chats: 2 }, { chats: 1 }]

omitByIndexed()

returns an object the same as the provided one but without the fields omitted by the predicate function

Kind: global function
Example

omitByIndexed((val, key) => key === 'b', { a: 1, b: 2, c: 3 })
// returns { a: 1, c: 3 }

omit()

returns the provided object but with specified keys omitted

Kind: global function
Example

omit(['a'], { a: 1, b: 2 })
// returns { b: 2 }

omitBy()

returns an object same as the provided one but without the fields omitted by the predicate function

Kind: global function
Example

omitBy(el => el % 2 === 0, { a: 1, b: 2, c: 3 })
// returns { a: 1, c: 3 }

once()

returns a particular function to be executed only a single time

Kind: global function
Example

const results = [1, 2, 3, 4, 5]
const getResult = once(() => results.pop())
getResult() // 5
getResult() // 5
getResult() // 5

over()

returns a function that called invokes the provided array of functions with the call arguments

Kind: global function
Example

const func = over([val => val + 1, val => val * 10, Boolean])
func(1)
// returns [2, 10, true]

takeLast()

returns the specified amount of the provided array elements starting from the end

Kind: global function
Example

takeLast(2, ['a', 'b', 'c', 'd'])
// returns ['c', 'd']

overArgs()

returns a function that called invokes the provided arguments transformers

Kind: global function
Example

const func = overArgs((a, b, c) => [a, b, c], [n => n * n, Boolean])
func(2, 0, 1)
// returns [4, false, 1]

pair()

returns a tuple from the two provided values

Kind: global function
Example

pair('a', 'b')
// returns ['a', 'b']

partitionObject()

returns a tuple of valid and invalid parts of the object as defined in validation function passed in the first argument

Kind: global function
Example

partitionObject(el => el % 2 === 0, { a: 1, b: 2, c: 3 })
// returns [{ b: 2 }, { a: 1, c: 3 }]

pick()

picks specified properties from the object

Kind: global function
Example

pick(['b'], { a: 1, b: 2 })
// returns { b: 2 }

pickBy()

returns an object same as the provided one but with the fields picked by the predicate function

Kind: global function
Example

pickBy(el => el % 2 === 0, { a: 1, b: 2, c: 3 })
// returns { b: 2 }

pickByIndexed()

returns an object same as the provided one but with the fields picked by the predicate function

Kind: global function
Example

pickByIndexed((val, key) => key === 'b', { a: 1, b: 2, c: 3 })
// returns { b: 2 }

pickOwn()

picks specified props only if they exist on the provided object

Kind: global function
Example

pickOwn(['b'], { a: 1, b: 2 })
// returns { b: 2 }

randomInt()

returns a random integer number between the specified min and max values

Kind: global function
Example

randomInt(0, 10)
// returns 7

range()

returns an array filled with numbers in an ascending order to the provided max value

Kind: global function
Example

range(5)
// returns [0, 1, 2, 3, 4, 5]

reject()

returns an array with elements that return false for the provided predicate function

Kind: global function
Example

reject(el => el % 2 === 0, [1, 2, 3, 4, 5])
// returns [1, 3, 5]

removeAt()

returns the provided array without the specified index element

Kind: global function
Example

removeAt(2, [1, 2, 3, 4, 5])
// returns [1, 2, 4, 5]

set()

sets the property of the provided object specified by the provided path in form of a string or an array of keys

Kind: global function
Example

const obj = { a: 1, b: { c: 2 } }
set('b.d', 3, obj)
// returns { a: 1, b: { c: 2, d: 3 } }
set(['b', 'd'], 3, obj)
// returns { a: 1, b: { c: 2, d: 3 } }

shallowEqual()

returns true if the provided values are shallow equal

Kind: global function
Example

shallowEqual({ a: 1 }, { a: 1 })
// returns true
shallowEqual({ a: { b: 1 } }, { a: { b: 1 } })
// returns false

shortenLongText()

shortens the provided string by the specified amount

Kind: global function
Example

shortenLongText(5, 'Lorem ipsum dolor')
// returns 'Lorem...'

sign()

returns a sign of the provided number or NaN if value different than number was provided

Kind: global function
Example

sign(10)
// returns 1
sign(-8)
// returns -1

shuffle()

returns an array with the provided array values shuffled

Kind: global function
Example

shuffle([1, 2, 3, 4])
// returns [4, 1, 3, 2]

sliceDiff()

returns the diff object from the provided object and slice comparison

Kind: global function
Example

sliceDiff({ a: 1, b: 10, g: 3 }, { a: 1, b: 2, c: 3 })
// returns { b: 10, g: 3 }

snakeCase()

snake cases the provided string

Kind: global function
Example

snakeCase('helloWorld')
// returns 'hello_world'

someAreTruthy()

returns true if some of the array values is truthy

Kind: global function
Example

someAreTruthy([0, 1, 2])
// returns true

splitAt()

splits an array or a string at the given index

Kind: global function
Example

splitAt(2, [1, 2, 3, 4, 5])
// returns [[1, 2], [3, 4, 5]]
splitAt(2, 'foobar')
// returns ['fo', 'obar']

splitRightWhenAccum()

returns a tuple with the provided array splited on an element that returned true for the provided function, iterating from the right side

Kind: global function
Example

splitRightWhenAccum((el, acc) => [el % 2 === 0, acc], [], [1, 2, 3, 4])
// returns [[1, 2, 3], [4]]

spread()

returns a function that called with an array of values calls the provided function with the spreaded arguments from the array arguments

Kind: global function
Example

const func = spread((a, b, c) => a + b + c)
func([1, 2, 3])
// returns 6

sum()

returns a sum of all the provided array number values

Kind: global function
Example

sum([1, 2, 3])
// returns 6

take()

returns the specified amount of the provided array elements starting from the beginning

Kind: global function
Example

take(2, ['a', 'b', 'c', 'd'])
// returns ['a', 'b']

takeRightWhileFrom()

takes elements while predicate returns true starting from the right from the specified index

Kind: global function
Example

takeRightWhileFrom(el => el > 2, 3, [1, 2, 3, 4, 5])
// returns [3, 4]

takeRightWhile()

takes elements while predicate returns true

Kind: global function
Example

takeRightWhile(el => el > 2, [1, 2, 3, 4, 5])
// returns [3, 4]

throttle()

ensures that a function is executed at a fixed interval, so that it is not called too frequently

Kind: global function
Example

const updatePreview = () => { ... }
const throttledUpdatePreview = throttle(updatePreview, 500);
inputField.addEventListener('input', throttledUpdatePreview);

toArray()

converts values that are iterable to an array

Kind: global function
Example

toArray('hello')
// returns ['h', 'e', 'l', 'l', 'o']

toFixedNumber()

returns the provided number with specified amount of decimal digits

Kind: global function
Example

toFixedNumber(1.2345, 2)
// returns 1.23

toPairs()

returns an array of derived from the provided object key-value tuples

Kind: global function
Example

toPairs({ a: 1, b: 2 })
// returns [['a', 1], ['b', 2]]

trailingThrottle()

ensures that a function is executed at a fixed interval, so that it is not called too frequently

Kind: global function
Example

const updatePreview = () => { ... }
const throttledUpdatePreview = trailingThrottle(updatePreview, 500);
inputField.addEventListener('input', throttledUpdatePreview);

leadingThrottle()

ensures that a function is executed at a fixed interval, so that it is not called too frequently

Kind: global function
Example

const updatePreview = () => { ... }
const throttledUpdatePreview = leadingThrottle(updatePreview, 500);
inputField.addEventListener('input', throttledUpdatePreview);

stringCompare()

returns 0 for matching strings return -1 for string with lower char code at some position return 1 for string with greater char code at some position

Kind: global function
Example

stringCompare('abc', 'abc')
// returns 0
stringCompare('abc', 'abd')
// returns -1

trimStart()

trims the beginning whitespaces from the provided string

Kind: global function
Example

trimStart('      hello')
// returns 'hello'

trimEnd()

trims the end whitespaces from the provided string

Kind: global function
Example

trimEnd('hello     ')
// returns 'hello'

repeat()

returns the provided string repeated the specified amount of times

Kind: global function
Example

repeat(3, 'test')
// returns 'testtesttest'

uniqBy()

returns an array with all the duplicates from the provided array removed based on the iteratee function

Kind: global function
Example

uniqBy(el => el.toString(), [1, '1', 2, '3', 3])
// returns [1, 2, '3']

uniq()

returns an array with all the duplicates from the provided array removed

Kind: global function
Example

uniq([1, 1, 2, 3, 3])
// returns [1, 2, 3]

update()

updates the provided array with the provided value on the specified index

Kind: global function
Example

update(2, 3, [1, 2, 5])
// returns [1, 2, 3]

without()

returns an array without the specified elements from the provided array

Kind: global function
Example

without([2, 4], [1, 2, 3, 4, 5])
// returns [1, 3, 5]

zipWith()

returns an array of tuples of certain index elements from two provided arrays based on the zipper function

Kind: global function
Example

zipWith((a, b) => [a * 2, b.toString()], [1, 2, 3], [10, 20, 30])
// returns [[2, '10'], [4, '20'], [6, '30']]

zip()

returns an array of tuples of certain index elements from two provided arrays

Kind: global function
Example

zip([1, 2, 3], [10, 20, 30])
// returns [[1, 10], [2, 20], [3, 30]]