fold-collection

A collection of useful functions using exclusively the 'fold'/'reduce' pattern

Install

$ npm install --save fold-collection

Documentation

• foldL
• foldR
• and
• any
• average
• composition
• count
• drop
• filter
• flatten
• forEach
• insertionSort
• join
• map
• mapFusion
• max
• member
• min
• negateAll
• or
• partition
• removeConsecutive
• replicate
• reverse
• size
• sum
• take

⬆ foldL(arr, f, init)

Higher-order function applied to arrays, based on the concept of accumulators (i.e. return a value from the accumulation). Left associative, tail recursive.

Parameters

arr: Array, Array to work on

f: function, Function to apply ('a -> 'b -> 'a)

init: *, Initial value

Returns: *

⬆ foldR(arr, f, init)

Higher-order function applied to arrays, based on the concept of accumulators (i.e. return a value from the accumulation). Right associative, not tail recursive.

Parameters

arr: Array, Array to work on

f: function, Function to apply ('a -> 'b -> 'a)

init: *, Initial value

Returns: *, The accumulated value

⬆ and(arr)

Applies the and operator to all the boolean expressions

Parameters

arr: Array, Array of boolean expressions

Returns: Boolean

⬆ any(arr, f)

Checks if a predicate is satisfied by any item

Parameters

arr: Array, Checks if a predicate is satisfied by any item

f: function, The predicate

Returns: Boolean

⬆ average(arr)

Gets the average of a list of numbers

Parameters

arr: Array, Gets the average of a list of numbers

Returns: number

⬆ composition(arr)

Merge a list of functions into one function

Parameters

arr: Array, Array of functions

Returns: function

⬆ count(arr, e)

Counts the number of occurrences of an element

Parameters

arr: Array, Counts the number of occurrences of an element

e: *, The element to check

Returns: Number

⬆ drop(arr, n)

Drops every 'n' times from 'arr'

Parameters

arr: Array, Drops every 'n' times from 'arr'

n: Number, Drops every 'n' times from 'arr'

Returns: Array, New array with the items deleted

⬆ filter(arr, f)

Filter the array based on a given property

Parameters

arr: Array, Filter the array based on a given property

f: function, The property/predicate to filter on

Returns: Array, The filtered array

⬆ flatten(arr, deep)

Flatten an array of arrays

Parameters

arr: Array, Array of arrays

deep: Boolean, Whether to perform a 'deep flattening'

Returns: Array, The flattened array

⬆ forEach(arr, f)

Performs a for loop

Parameters

arr: Array, Performs a for loop

f: function, The action to apply

⬆ insertionSort(arr)

Performs an insertion sort

Parameters

arr: Array, The array to sort

Returns: Array, The sorted array

⬆ join(arr, optional)

Join the items of an array into a string

Parameters

arr: Array, Join the items of an array into a string

optional: String, sep The separator. Default: ','

Returns: String, The resulting string

⬆ map(arr, f)

Creates a new array with the results of calling a provided function on every element

Parameters

arr: Array, Creates a new array with the results of calling a provided function on every element

f: function, Creates a new array with the results of calling a provided function on every element

Returns: Array, The new array

⬆ mapFusion(arr, fs)

Performs multiple maps

Parameters

arr: Array, Performs multiple maps

fs: Array, Array of functions to map

Returns: Array, The new array

⬆ max(arr)

Get the maximum item

Parameters

arr: Array, Get the maximum item

Returns: *

⬆ member(arr, e)

Checks whether 'e' is in 'arr'

Parameters

arr: Array, Checks whether 'e' is in 'arr'

e: *, The element to test

Returns: Boolean

⬆ min(arr)

Get the minimum item

Parameters

arr: Array, Get the minimum item

Returns: *

⬆ negateAll(arr)

Negate all numbers in the array

Parameters

arr: Array, Negate all numbers in the array

Returns: Array

⬆ or(arr)

Applies the or operator to all the boolean expressions

Parameters

arr: Array, Array of boolean expressions

Returns: Boolean

⬆ partition(arr, f)

Partitions the array the array over a property

Parameters

arr: Array, Partitions the array the array over a property

f: function, Partitions the array the array over a property

Returns: Object, Object with key 'T' corresponding to all elements satisfying the property. 'F' otherwise.

⬆ removeConsecutive(arr)

Remove consecutive items from an array

Parameters

arr: Array, Remove consecutive items from an array

Returns: Array, The array without consecutive values

⬆ replicate(arr, n)

Replicate the items 'n' times

Parameters

arr: Array, Replicate the items 'n' times

n: Number, The replication amount

Returns: Array

⬆ reverse(arr)

Reverse an array

Parameters

arr: Array, Reverse an array

Returns: Array, The reversed array

⬆ size(arr)

Get the length of an array

Parameters

arr: Array, Get the length of an array

Returns: Number, Length

⬆ sum(arr)

Get the sum of an array of numbers

Parameters

arr: Array, Get the sum of an array of numbers

Returns: Number

⬆ take(arr, n)

Take just the elements at the nth position

Parameters

arr: Array, Take just the elements at the nth position

n: Number, nth position

Returns: Array

Examples

Check the test file

License

MIT © Ossama Edbali