futil

A collection of F(unctional) Util(ities). Resistance is futile.

Mostly, these are generic utilities that could conceivably be part of a library like lodash/fp, but for some reason or other are not.

Version History/Changelog

See our changelog

Installing

npm i -S futil-js

This package requires lodash/fp, so make sure that's available in your app.

API

Function

maybeCall

(fn, a, b) -> fn(a, b) If fn is a function, call the function with the passed-in arguments. Otherwise, return false.

overNone

([f, g]) -> !f(x) && !g(x) Creates a function that checks if none of the predicates return truthy when invoked with the arguments it receives.

Collection

flowMap

...fns:functions -> map:function Runs a map function that runs a flow of the functions passed in to this method.

Lodash Conversions

These are conversions of lodash fp methods.

Ins (Rearg False)

getIn, includesIn, pickIn lodash/fp is great, but sometimes the curry order isn't exactly what you want. These methods provide alternative orderings that are sometimes more convenient. The idea of In methods is to name them by convention, so when ever you need a method that actually takes the collection first (e.g. a get where the data is static but the field is dynamic), you can just add In to the end (such as getIn which takes the object first)

Ons (Immutable False)

extendOn, defaultsOn lodash/fp likes to keep things pure, but sometimes JS can get pretty dirty. These methods are alternatives for working with data that--for whatever the use case is--needs to be mutable Any methods that interact with mutable data will use the On convention (as it is some action occuring On some data)

Array

compactJoin

join:string -> data:array -> result:string Joins an array after compacting.

dotJoin

data:array -> result:string Compacts and joins an array with '.'

repeated

data:array -> result:array Returns an array of elements that are repeated in the array.

Object

singleObject

(k, v) -> {k: v} Creates an object with a key and value.

singleObjectE

(v, k) -> {k: v} Flipped version of singleObject.

chunkObject

({a, b}) -> [{a}, {b}] Breaks an object into an array of objects with one key each.

compactObject

Remove properties with falsey values.

Example: ({ a: 1, b: null, c: false }) -> {a:1}

isEmptyObject:

Check if the variable is an empty object ({}).

isNotEmptyObject:

Check if the variable is not an empty object ({}).

stripEmptyObjects

Omit properties whose values are empty objects.

Example: { a:1, b:{}, c:2 } -> {a:1, c:2} (TODO remame to omitEmptyObjects)

compareDeep

Checks if an object's property is equal to a value.

matchesSignature

Returns true if object keys are only elements from signature list. (but does not require all signature keys to be present)

pickInto

TODO

renameProperty

from:string -> to:string: -> target:object -> result:object Rename a property on an object.

Example: renameProperty('a', 'b', {a:1}) -> {b:1)

unwind

Just like mongo's $unwind.

Example: { x:['a','b'], y:1 } -> [{ x:'a', y:1 }, { x:'b', y:1 }]

flattenObject

Flatten an object with the paths for keys.

Example: { a: { b: { c: 1 } } } => { 'a.b.c' : 1 }.

String

parens

'asdf' -> '(asdf)' Wraps a string in parenthesis.

Misc

testRegex

regex -> string -> bool Just like rambda test, creates a function to test a regex on a string.

Math

greaterThanOne

number -> bool Returns true if number is greater than one.

Algebras or composable/recursive data types

map

map :: (a -> b) -> [a] -> [b] Maps a function over an iterable. Works by default for Arrays and Plain Objects.

deepMap

deepMap :: (a -> b) -> [a] -> [b] Maps a function over a recursive iterable. Works by default for nested Arrays, nested Plain Objects and mixed nested Arrays and Plain Objects. Also works for any other iterable data type as long as two other values are sent: a mapping function, and a type checker (See the unit tests for deepMap).