jsutils2 v2.0.0

Any examples shown don't use require or any of that. The examples are shown as if they are imported using a <script> tag.

Documentation

Any

Exists

exists :: any => boolean

Checks if a value exists. (if it isn't undefined or null)

exists(5);
=> true
exists([2, 3][4]);
=> false

Identity

identity :: any => any

Returns the passed parameter. Can be used to evaluate a boolean value like i < 3.

identity(5);
=> 5
identity(3 < 4);
=> true

Print

print :: (...any) => void

Prints any number of values to the console. Each value is on a separate line.

Note: Will not work properly with the Firefox dev console, and probably some other devices. This works best in some text editors such as Atom.io.

print(2, 3, 4);
=> 2
=> 3
=> 4

Array

Apply

apply :: (array, function) => any

Applies a function that accepts spread arguments to an array.

apply([2, 3, 4, 5], Math.min); //Applies Math.min, which usually takes spread arguments, to the array passed in
=> 2

Choice

choice :: array | string => any

Selects a random value from an array. This can work on strings as well, as they are indexable.

repeat(10, () => print(choice([1, 2, 3, 4, 5, 6])));
=> 1
=> 6
=> 4
=> 2
=> 2
=> 3
=> 5
=> 1
=> 5
=> 1

Concat

concat :: (any, any) => array

Joins any 2 items into a single array. Can join 2 arrays together as well.

concat(2, 3);
=> [2, 3]
concat([5, 3], [4, 2]);
=> [5, 3, 4, 2]

ConcatAll

concatAll :: array => array

Joins all items of an array into a single array. This effectively flattens the top layer of an array.

concatAll([2, 3, [4, 5], [6, 7]]);
=> [2, 3, 4, 5, 6, 7]
concatAll([3, [4, [5, 6]], [7, 8]]);
=> [3, 4, [5, 6], 7, 8]

Count

count :: (array, function) => number

Counts the number of elements in an array that meet a condition.

count([2, 3, 4, 5], e => e < 4);

DropWhile

dropWhile :: (array, function) => array

Drops items from an array that meet a condition until it finds one that doesn't meet a condition.

dropWhile([5, 3, 1, 6, 8, 7, 9], isOdd);
=> [6, 8, 7, 9]

Flatten

flatten :: array => array

Flattens an array down to a one-dimensional array.

flatten([[[2, 3], 4, 5], [6, 7], 8]);
=> [2, 3, 4, 5, 6, 7, 8]

Head

head :: array => any

Gets the first value of an array.

head([2, 3, 4]);
=> 2

Insert

insert :: (array, index: number, item: any) => array

Inserts an item at a specific index of an array.

insert([2, 3, 4, 5, 6], 1, 7);
=> [2, 7, 3, 4, 5, 6]

IsArray

isArray :: any => bool

Returns if a given value is an array.

isArray(5);
=> false
isArray([2, 3]);
=> true

Max

max :: array<number> => number

Returns the largest value of an array.

max([5, 2, 9, 10, 6, 3]);
=> 10

Min

min :: array<number> => number

Returns the smallest value of an array.

min([5, 2, 9, 10, 6, 3]);
=> 2

None

none :: (array, function) => boolean

Returns if none of the values of an array meet a condition.

none([2, 3, 4, 5], e => e < 4);
=> false
none([2, 3, 4, 5], e => e < 1);
=> true

Product

product :: array<number> => number

Gets the product of the values of the array.

product([5, 7, 3]);
=> 105

Quicksort

quicksort :: array<number> => array<number>

Sorts an array using the Quicksort algorithm.

quicksort([5, 2, 9, 8, 1, 7, 3]);
=> [1, 2, 3, 5, 7, 8, 9]

Range

range :: (low: number, high: number?, step: number? = 1) => array<number>

Creates a range of numbers between 2 values, with a given step. Based on Python's built-in range function.

range(1, 11);
=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
range(2, 13, 3);
=> [2, 5, 8, 11]
range(5, -5, -1);
=> [5, 4, 3, 2, 1, 0, -1, -2, -3, -4]
range(5);
=> [0, 1, 2, 3, 4]

Reject

reject :: (array, function) => array

Returns a version of an array without any items that meet a condition.

reject([2, 3, 4, 5, 7, 8, 9, 11], isEven);
=> [3, 5, 7, 9, 11]

RemoveEachItem

removeEachItem :: (array, item: any) => array

Removes every instance of a value from an array.

removeEachItem([2, 3, 4, 3, 5, 6], 3);
=> [2, 4, 5, 6]

RemoveIndex

removeIndex :: (array, index: number) => array

Removes a value at an index from an array.

removeIndex([2, 3, 4, 5, 6], 2);
=> [2, 3, 5, 6]

RemoveItem

removeItem :: (array, item: any) => array

Removes a specific item from an array. (Only 1 instance of the item)

removeItem([2, 3, 4, 5, 6], 3);
=> [2, 4, 5, 6]

ReplaceEachItem

replaceEachItem :: (array, item: any, item2: any) => array

Replaces each instance of a value in an array with a different value.

replaceEachItem([2, 3, 4, 3, 5, 6], 3, 7);
=> [2, 7, 4, 7, 5, 6]

Reverse

reverse :: array => array

Reverses an array. Operates as a pure function, to avoid modifying the original array.

reverse([2, 3, 4]);
=> [4, 3, 2]

Partition

partition :: (array, function) => array<array>

Splits an array into 2 arrays, where one contains items that meet a condition, and the second contains items that don't.

partition([2, 3, 4, 5, 7, 8, 9, 11], isEven);
=> [[2, 4, 8], [3, 5, 7, 9, 11]]

PartitionWith

partitionWith :: (array, ...function) => array<array>

Returns an array of arrays, where each array successively contains items that meet a condition.

partitionWith([2, 3, 4, 5, 7, 8, 9, 11], isEven, e => isDivisible(e, 3));
=> [[2, 4, 8], [3, 9], [5, 7, 11]]

Shuffle

shuffle :: array => array

Shuffles the values in an array randomly.

repeat(10, () => print(shuffle([1, 2, 3, 4, 5, 6])));

=> [3, 1, 2, 6, 5, 4]
=> [5, 2, 6, 4, 3, 1]
=> [5, 2, 3, 6, 4, 1]
=> [2, 4, 3, 1, 5, 6]
=> [3, 2, 1, 5, 4, 6]
=> [1, 6, 4, 3, 5, 2]
=> [2, 5, 1, 6, 3, 4]
=> [5, 6, 1, 3, 4, 2]
=> [5, 3, 1, 6, 2, 4]
=> [2, 3, 6, 1, 5, 4]

Sum

sum :: array<Addable> => Addable

Adds together each item of an array. The Addable notation applies to anything that works with the + operator, which means numbers and strings.

sum([2, 3, 4, 5]);
=> 14
sum(["str", "ing"]);
=> "string"

Tail

tail :: array => array

Returns everything except for the first value of an array. If the array has one item, it returns an empty array.

head([2, 3, 4]);
=> [3, 4]

TakeWhile

takeWhile :: (array, function) => array

Takes items from an array while they meet a condition.

takeWhile([2, 4, 6, 8, 1, 7, 9, 8], isEven);
=> [2, 4, 6, 8]

ToArray

toArray :: any => array

Converts a given value to an array. If the value is already an array, it remains as it is.

toArray(5);
=> [5]
toArray([5]);
=> [5]

Functional

Compose

compose :: (...function) => any => any

Returns a function that applies any number of functions in natural order. Works very well with currying and partial application.

compose(e => e / 2, square)(3);
=> 4.5

Partial

partial :: (function, ...any) => (...any) => any

Returns a function that applies any number of arguments to a function, and which accepts any number of arguments to complete the function.

partial(Math.max, 2, 3, 4)(5, 1);
=> 5

ReverseArgs

reverseArgs :: function => (...any) => any

A variant of spreadArgs that operates in reverse order.

reverseArgs(concatAll)([2, 3], [4, 5], [6, 7]);
=> [6, 7, 4, 5, 2, 3]

Sequence

sequence :: (...function) => any => any

Returns a function that applies any number of functions in reverse order. Works very well with currying and partial application.

sequence(e => e / 2, square)(3);
=> 2.25

SpreadArgs

spreadArgs :: function => (...any) => any

Converts a function that takes an array to one that takes a spread.

spreadArgs(sum)(2, 3, 4);
=> 9

Math

Accumulator Functions

:: (number, number) => number

These functions accept 2 operators, and are designed to be used with reduce and similar functions.

• add
• subtract
• multiply
• divide
• mod
• pow (works like Math.pow)
• bitor (bitwise operators)
• bitand
• bitxor
• leftshift (bitshifts)
• rightshift

Cbrt

cbrt :: number => number

Gets the cube root of a number. Alias for Math.cbrt.

cbrt(64);
=> 4

Cosine

cosine :: number => number

Version of Math.cos which returns degrees.

cosine(60);
=> 0.5

Cube

cube :: number => number

Cubes a number.

cube(5);
=> 125

Factorial

number :: number => number

Gets the factorial of a number.

factorial(10);
=> 3628800

Floor

floor :: (number, number? = 0) => number

Rounds a given number down to a specific number of decimal places.

floor(20.56, 1);
=> 20.5

IsBetween

isBetween :: (number, number, number) => boolean

Returns if a number is between 2 other numbers.

isBetween(5, 4, 6);
=> true
isBetween(3, 4, 6);
=> false

IsDivisible

isDivisible :: (number, number) => boolean

Checks if 2 numbers are divisible by each other.

isDivisible(9, 3);
=> true
isDivisible(5, 4);
=> false

IsEven

isEven :: number => number

Checks if a number is an even number.

isEven(6);
=> true
isEven(5);
=> false

IsFibonacci

isFibonacci :: number => number

Checks if a number is a Fibonacci number.

isFibonacci(55);
=> true
isFibonacci(57);
=> false

IsOdd

isOdd :: number => number

Checks if a number is an odd number.

isOdd(5);
=> true
isOdd(6);
=> false

IsPrime

isPrime :: number => number

Checks if a number is a prime number.

isPrime(59);
=> true
isPrime(63);
=> false

IsWhole

isWhole :: number => boolean

Checks if a number is a whole number.

isWhole(7);
=> true
isWhole(6.6);
=> false

NRoot

nRoot :: (number, number) => number

Gets the nth root of a number.

nRoot(81, 3);
=> 4

PI

PI :: number

An alias for Math.PI.

RandInt

randInt :: (low: number, high: number) => number

Generates a random number between 2 other numbers.

repeat(10, () => print(randInt(1, 6)));
=> 5
=> 1
=> 5
=> 1
=> 3
=> 4
=> 2
=> 2
=> 3
=> 3

Random

random :: () => number

Alias for Math.random.

Round

round :: (number, number? = 0) => number

Rounds a given number to a specific number of decimal places.

round(20.53, 1);
=> 20.5

Sine

sine :: number => number

Version of Math.sin which returns degrees.

sine(60);
=> 0.8660254038...

Sqrt

sqrt :: number => number

Gets the square root of a number. Alias for Math.sqrt.

sqrt(16);
=> 4

Square

square :: number => number

Squares a number.

square(5);
=> 25

Tangent

tangent :: number => number

Version of Math.tan which returns degrees.

tangent(60);
=> 1.73205080757...

Triangular

triangular :: number => number

Converts a number to a corresponding triangular number.

triangular(10);
=> 55

Object

HasKey

hasKey :: (object, any) => boolean

Checks if an object has a key.

hasKey({2: 3, 3: 4}, 3);
=> true
hasKey({2: 3, 3: 4}, 1);
=> false

Pluck

pluck :: (object, any) => any

Extracts a value from an object. Good for map and related functions.

pluck({1: 2, 2: 3}, 2);
=> 3

String

StrShuffle

strShuffle :: string => string

Shuffles the characters in a string.

repeat(10, () => print(shuffle("string")));
=> "snirtg"
=> "gnirst"
=> "tingsr"
=> "gnrits"
=> "igtnrs"
=> "irtgns"
=> "rgtins"
=> "stgrin"
=> "nsitgr"
=> "trnsgi"

StrInsert

strInsert :: (string, index: number, item: string) => string

Inserts a string at a specific index of a string.

strInsert("string", 2, "ar")
=> "starring"

StrRemoveEachItem

strRemoveEachItem :: (string, item: any) => string

Removes every instance of a value from a string.

strRemoveEachItem("string is a string", "string");
=> " is a "

StrRemoveIndex

strRemoveIndex :: (string, index: number) => string

Removes a value at an index from a string.

strRemoveIndex("string", 2);
=> "sting"

StrRemoveItem

strRemoveItem :: (string, item: any) => string

Removes a specific item from a string. (Only 1 instance of the item)

strRemoveItem([2, 3, 4, 5, 6], 3);
=> [2, 4, 5, 6]

StrReverse

strReverse :: string => string

Reverses a string without modifying the original string.

strReverse("string");
=> "gnirts"

Structures

Repeat

repeat :: (number, function)

Executes a given function a certain number of times. It can accept arguments in the function.

repeat(5, () => print("Hello world!"));
=> "Hello world!"
=> "Hello world!"
=> "Hello world!"
=> "Hello world!"
=> "Hello world!"

Until

until :: (cond: function, function)

Executes a function until the condition is true.

let i = 1;

until(() => i > 10, () => {
    print(i);
  	i++;
});
=> 1
=> 2
=> 3
=> 4
=> 5
=> 6
=> 7
=> 8
=> 9
=> 10