hu ![Build Status][travis] ![NPM version][npm] !Total Downloads

hu is a functional-oriented generic utility helper library inspired by Haskell's prelude and Lodash/Underscore/Ramda.

Unlike other well-known libraries, hu only provides a reduced but very common set of useful functions.
It aims to be a lightweight and small library which can be easily embedded as a part of an application, library or framework without making noise.

hu library works well in ES5 compliant engine. Most of its functions are implicitly curried.

Features

- Complete and reliable type checking helpers
- Collection and object iterators
- Array and objects processors and transformers helpers
- Functional composition and async (curry, partial, compose, memoize, defer...)
- String manipulation helpers
- Equality comparison functions, including deep comparison
- Runs in node.js and browsers
- Well tested with 100% of coverage
- Small (~800 SLOC)
- Dependency free

Installation

#### Node.js

``bash $ npm install hu --save`

#### Browser

Via Bower`bash $ bower install hu`

Via Component`bash $ component install h2non/hu`

Or load the script remotely (just for testing or development)`html`

`Browsers Support`

!Chrome | !Firefox | !IE | !Opera | !Safari --- | --- | --- | --- | --- | +5 | +3.5 | +9 | +10.6 | +5 |

`Why hu?`

`$3`

Functional programming tendency has grown (again) in the last years. This paradigm, unlike others that may be more totalitarian and extended, forces a radical re-thinking in the way that programmers design and implement software.

Functional programming thinking and conversion is not always easy to apply, but it's really a quite attractive and funny paradigm which could helps a lot when solving certaing kind of problems in a more theoretically and conceptually clean way, and tipically more efficiently.

`$3`

A good approach to learn and apply functional programming principles is creating a functional-oriented library that assists by itself to do functional programming

In fact, hu was created to define a real scenario to do funny experiments with some pure functional programming principles

It's completely written in [Wisp][wisp], a homoiconic Clojure-like language, which compiles into plain JavaScript that supports s-expressions and macros, allowing to extend the compiler features with the user’s own code

`$3`

JavaScript is an ubiquitous, well-extended, multi-purpose and multi-paradigm cool language with which you can do a lot of funny things

Yes, I know, JavaScript is not a pure functional language, however its natural extensibility and meta-programming capabilities allows you to apply different paradigms to it and today there are a lot of languages that transpile into JavaScript that help providing a powerful syntax sugar and more features, like in this case using Wisp.

`$3`

hu is implemented keeping in mind the following “ambitious” functional focused goals:

- Assume it's a first-class function only language - Pure functions as a norm - Immutability (when it's possible) - Avoid assignment, remove side-effects (when it's possible) - Tend to recursion instead of loops - Tend to high-order functions - Tend to functional composition - Tend to continuation-passing style - Exploit subroutines (like tail recursion call) - Exploit function memorization (currying, partial, caching...) - Macros are a great thing when used right¡, don't have fear.

`API`

- Type checking - isBool - isNumber - isFinite - isNaN - isString - isSymbol - isFunction - isDate - isRegExp - isArray - isObject - isPlainObject - isError - isElement - isArgs - isUndef - isNull - isEmpty - notEmpty - isMutable - isPrimitive - isIterable - Strings - subs - lines - unlines - words - unwords - chars - unchars - char - reverse - repeat - escape - Numbers - odd - even - lower - higher - max - min - inc - dec - signum - isNegative - negate - recip - div - max - min - abs - round - random - floor - sin - tan - cos - asin - atan - atan2 - ceil - exp - sqrt - PI - Arrays - inArray - head - tail - last - initial - flatten - Objects - has - keys - vals - keyValues - toObject - extend - mixin - map - filter - clone - merge - Collections - each - size - compact - Functions - constant - apply - bind - partial - curry - compose - memoize - wrap - once - throttle - times - defer - debounce - Equality - isEqual - isPatternEqual - isDateEqual - isArrayEqual - isObjectEqual - Miscellaneous - log - isBrowser - noop - now - _global

`$3`

JavaScript Harmony (ES6)`js var { log, filter, even, inc } = require('hu')

log(map(filter({a: 1, b: 2}, even), inc)) // → { b: 3 }`

Or with the funny LiveScript`livescript (a: 1, b: 2) |> filter _, even |> map _, inc |> log`

`$3`

#### isBool(value) Return:boolean | Alias: isBoolean

Checks if the given value is a boolean type

#### isNumber(value) Return:boolean

Checks if the given value is a number type

#### isFinite(value) Return:boolean

Checks if the given value is a finite number, or it can be coerced into it

#### isNaN(value) Return:boolean

Is it NaN (not a number)? More accurate than the native isNaN function

#### isString(value) Return:boolean

Checks if the given value is a string type

#### isSymbol(value) Return:boolean

Checks if the given value is a symbol type

#### isFunction(value) Return:boolean | Alias: isFn

Checks if the given value is a function type

#### isDate(value) Return:boolean

Checks if the given value is a date type

#### isRegExp(value) Return:boolean | Alias: isPattern

Checks if the given value is a regexp type

#### isArray(value) Return:boolean

Checks if the given value is an array type

#### isObject(value) Return:boolean

Checks if the given value is an object type

#### isPlainObject(value) Return:boolean

Checks if the given value is a native object type (it was createdd by the Object native constructor)

#### isError(value) Return:boolean

Checks if the given value is an error type

#### isElement(value) Return:boolean

Checks if the given value is a DOM element object instance

#### isArgs(value) Return:boolean | Alias: isArguments

Checks if the given value is an arguments object

#### isUndef(value) Return:boolean | Alias: isUndefined

Checks if the given value is a undefined, void o null type

#### isNull(value) Return:boolean

Checks if the given value is a null type

#### isEmpty(value) Return:boolean

Checks if the given value is empty. Arrays, strings, or arguments objects with a length of 0 and objects with no own enumerable properties are considered empty values

#### notEmpty(value) Return:boolean | Alias: isNotEmpty

Checks if the given value is not empty

#### isMutable(value) Return:boolean

Checks if the given value is a mutable data type. Objects, arrays, date objects, arguments objects and functions are considered mutable data types

#### isPrimitive(value) Return:boolean

Checks if the given value is a primitive value type. Strings, numbers, booleans, symbols and null are considered primitives values

#### isIterable(value) Return:boolean | Alias: canIterate

Checks if the given value can be iterated. Objects, arrays, and arguments objects are considered iterables data types

`$3`

#### subs(str, start, end) Return:string

Extract characters from the given string

#### lines(str) Return:array

Split the given string by end of line tokens

#### unlines(arr) Return:string

Join the given array into a string separated by end line token

#### words(str) Return:array

Returns an array of words (spaces separated)

#### unwords(arr) Return:string

Join words of the given array into a string spaces separated

#### chars(str) Return:array

Return an array of characters of the given string

#### unchars(arr) Return:string

Join the strings of the given array

#### char(number) Return:string

Return the given unicode number into his equivalent character

#### reverse(str) Return:string

Reverse characters of the given string

#### repeat(number, str) Return:string

Repeat the given string

#### escape(str) Return:string

Converts the characters &, <, >, ", and ' in the given string to their corresponding HTML entities

`$3`

#### odd(number) Return:boolean | Alias: isOdd

Returns true if the given number is odd

#### even(number) Return:boolean | Alias: isEven

Returns true if the given number is even

#### lower(x, y) Return:boolean | Alias: isLower | Curried: true

Returns true if x it's lower than y

#### higher(x, y) Return:boolean | Alias: isHigher | Curried: true

Returns true if x it's lower than y

#### max(...numbers) Return:number

Returns the number with the highest value

#### min(...numbers) Return:number

Returns the number with the lower value

#### inc(number) Return:number

Increment the given value

#### dec(number) Return:number

Decrement the given value

#### signum(number) Return:number

Takes a number and returns either -1, 0, or 1 depending on the sign of the number

#### isNegative(number) Return:boolean

Returns true if the given number is negative

#### negate(number) Return:number

The negation of the given number

#### recip(number) Return:number

One over the number: ie 1 / x

#### div(number) Return:number

Division truncated down toward negative infinity

#### max(...numbers) Return:number

Returns the largest of zero or more numbers

#### min(...numbers) Return:number

Returns the smallest of zero or more numbers

#### abs(number) Return:number

Returns the absolute value of a number

#### round(number) Return:number

Returns the value of a number rounded to the nearest integer

#### random() Return:number

Returns a pseudo-random number between 0 and 1

#### floor(number) Return:number

Returns the largest integer less than or equal to a number

#### sin(number) Return:number

Returns the sine of a number

#### tan(number) Return:number

Returns the tangent of a number

#### cos(number) Return:number

Returns the cosine of a number

#### asin(number) Return:number

Returns the arcsine of a number

#### atan(number) Return:number

Returns the arctangent of a number

#### atan2(number) Return:number

Returns the cosine of a number

#### ceil(number) Return:number

Returns the smallest integer greater than or equal to a number

#### exp(number) Return:number

Returns Ex, where x is the argument, and E is Euler's constant (2.718...), the base of the natural logarithm

#### sqrt(number) Return:number

Returns the positive square root of a number

#### PI Type:number

Ratio of the circumference of a circle to its diameter, approximately 3.14159

`$3`

#### inArray(arr, element) Return:boolean | Curried: true

Checks if an element exists in the given array

#### head(arr) Return:mixed | Alias: first

First item of the given array

`js hu.head([1, 2, 3]) // → 1`

#### tail(arr) Return:array | Alias: rest

Everything but the first item of the list

`js hu.tail([1, 2, 3]) // → [2, 3]`

#### last(arr) Return:mixed | Alias: end

The last item of the list

`js hu.last([1, 2, 3]) // → 3`

#### initial(arr) Return:array

Everything but the last item of the list

`js hu.initial([1, 2, 3]) // → [1, 2]`

#### flatten(arr) Return:array

Recursively flatten elements of a multidimensional list into a one dimension list.

`js hu.flatten([1, [2], [3, [4, [5]]]]) // → [1, 2, 3, 4, 5]`

`$3`

#### has(obj, property) Return:boolean

Checks if the specified property name exists as a own property of the given object

`js hu.has({a: true}, 'a') // → true`

#### keys(obj) Return:array

Returns a sequence of the map's keys

`js hu.keys({a: true}) // → ['a']`

#### vals(obj) Return:array

Returns a sequence of the map's values

`js hu.vals({a: true}) // → [true]`

#### keyValues(obj) Return:array | Alias: pairs

Returns a two dimensional array of an object’s key-value pairs

`js hu.keyValues({a: true}) // → [['a', true]]`

#### toObject(obj) Return:array

Creates an object of given arguments. Odd indexed arguments are used for keys and evens for values

`js hu.toObject('a', true) // → {a: true}`

#### extend(target, ...origins) Return:object | Alias: assign

Assigns own enumerable properties of source object(s) to the destination object

`js hu.extend({x: true}, {y: false}) // → {x: true, y: false}`

#### mixin(target, ...origins) Return:object

Adds function properties of a source object to the destination object

`js var methods = { something: function () { // cool stuff } } hu.mixin({x: true}, methods) // → {x: true, something: function () {}}`

#### map(obj, function) Return:object | Alias: mapValues | Curried: true

Maps object values by applying with the value return of each callback call on each one

`js function mapper(val) { return val * 2 } hu.map({x: 2}, mapper) // → {x: 4}`

#### filter(obj, function) Return:object | Alias: filterValues | Curried: true

Iterates over properties of an object, returning an filtered new object of all elements where the callback returns true

`js function filter(val) { return val > 1 } hu.map({x: 1, y: 2}, filter) // → {y: 2}`

#### clone(object) Return:object

Creates a clone of the given object

`js var obj = {x: 1} var newObj = hu.clone(obj) newObj === obj // → false`

#### merge(x, y) Return:object

Similar to extend, it returns an object that consists of the rest of the maps conj-ed onto the first

If a key occurs in more than one map, the mapping from the latter (left-to-right) will be the mapping in the result

`js var obj1 = {x: {y: {z: 2}}} var obj2 = {x: {y: {a: 1}}} var newObj = hu.merge(obj1, obj2) // → {x: {y: {z: 2, a: 1}}}`

`$3`

#### each(obj, function) Return:object | Alias: forEach

Iterates over elements of an iterable object, executing the callback for each element. It will return the same given object

`js hu.each([1, 2], function (n) { console.log('Value:', n) })`

#### size(obj) Return:number

Gets the size of the given collection

`js hu.size({x: 1, y: 2}) // → 2`

#### compact(obj) Return:object|array | Alias: clean

Returns a new collection which contains only the not empty values

`js hu.compact([1, null, undefined, "", 5]) // → [1, 5]`

`$3`

#### constant(value) Return:function | Alias: identity

Returns a function that returns the given value

`js var getter = hu.constant('john') getter() === 'john' // → true`

#### apply(fn, args) Return:mixed

Invokes a function binding itself function object context with the given arguments as array

`js function myFn(x, y) { return x * y } hu.apply(myFn, [2, 2]) // → 4`

#### bind(fn, ctx) Return:function

Creates a function that, when called, invokes the function with the this binding of thisArg and prepends any additional bind arguments to those provided to the bound function

`js function func(greeting) { return greeting + ' ' + this.name } func = hu.bind(func, { 'name': 'john' }, 'hi') func() // → 'hi john'`

#### partial(fn, [ ...partialArgs ]) Return:function

Creates a function that, when called, invokes func with any additional partial arguments prepended to those provided to the new function

`js function greet(greeting, name) { return greeting + ' ' + name; } var hi = hu.partial(greet, 'hi'); hi('john') // → 'hi john'`

#### curry(fn, [ ctx ]) Return:function

Creates a function which accepts one or more arguments of the given function that when invoked either executes the function returning its result

`js var curried = hu.curry(function(a, b, c) { console.log(a + b + c) }) curried(1)(2)(3) // → 6 curried(1, 2)(3) // → 6 curried(1, 2, 3) // → 6`

#### compose(...fn) Return:function

Creates a function that is the composition of the provided functions, where each function consumes the return value of the function that follows

`js function name(name) { return name.toLowerCase() + '!' } function greet(name) { return 'Hi ' + name } var welcome = hu.compose(name, greet); welcome('John') // → 'Hi john!'`

#### memoize(fn, resolver) Return:function

Creates a function that memoizes the result of the the given function. If resolver is provided it will be used to determine the cache key for storing the result based on the arguments provided to the memoized function. The resolver function just uses the first argument to the memoized function as the key

`js var multiply = hu.memoize(function (n) { return n * 2 }) multiply(2) // → 4 (computed value) multiply(2) // → 4 (memoized value)`

With custom resolver function to define memoized values`js var multiply = hu.memoize(function (n) { return n * 2 }, function (n) { return n === 2 ? n + 1 : n }) multiply(1) // → 2 (computed value) multiply(2) // → 4 (computed value) multiply(3) // → 4 (memoized value, from 2 value)`

#### wrap(fn, wrapperFn, [ ...args ]) Return:function | Curried: true

Creates a function that provides value to the wrapper function as its first argument. Additional arguments provided to the function are appended to those provided to the wrapper function

`js function hello(name) { return "hi " + name; } hello = hu.wrap(hello, function (fn, text, type) { return "before, " + fn("moe") + ", " + text + ": " + type + ", after" }, "type") hello("salutation") // → 'before, hi moe, type: salutation, after'`

#### once(fn) Return:function

Creates a function that is restricted to execute function once time. Subsuquents calls to the function will return the memoized value of the initial call

`js var times = 0 var init = hu.once(function () { return times += 1 }) init() // → 1 init() // → 1`

#### throttle(fn) Return:function | Curried: true

Creates a function that, when executed, will only call the fn function at most once per every wait milliseconds

`js var test = hu.throttle(function () { console.log(Date.now()) }, 100) test() // → first call test() // → no call setTimeout(test, 150) // → second call`

#### times(fn, number) Return:function | Curried: true

Creates a function that is restricted to be executed a finite number of times. Subsuquents calls to the function will return the memoized value of the latest call

`js var times = 0 var init = hu.times(function () { return times += 1 }, 2) init(); // → 1 init(); // → 2 init(); // → 2`

#### defer(fn, ms, [ ...args ]) Return:void

Executes the given function after wait milliseconds. You can provide arguments that will be passed to the function when it's invoked

`js function delayed(text) { console.log(text) } hu.defer(delayed, 1000, 'later') // → logs 'later' after one second`

#### debounce(fn, ms, [ ...args ]) Return:function

Return a function that executes the given function after wait milliseconds when it's called. You can provide arguments that will be passed to the function when it will be invoked

`js function delayed(text, name) { console.log(text, name) } var lazy = hu.debounce(delayed, 1000, 'later') lazy('call') // → logs 'later call' after one second`

`$3`

#### isEqual(x, y) Return:boolean | Alias: equal, deepEqual, 'isDeepEqual'

Compares primitives types and data objects in a type-independent manner. Clojure's immutable data structures define -equiv (and thus =) as a value, not an identity, comparison.

#### isPatternEqual(x, y) Return:boolean | Alias: isRegExpEqual, patternEqual | Curried: true

Check if the given dates are equal

#### isDateEqual(x, y) Return:boolean | Alias: dateEqual | Curried: true

Check if the given dates are equal

#### isArrayEqual(x, y) Return:boolean | Alias: arrayEqual | Curried: true

Check if the given arrays has the same elements

#### isObjectEqual(x, y) Return:boolean | Alias: objectEqual | Curried: true

Checks if the given objects values and keys are equals

`$3`

#### log(...msg) Return:undefined

Write the given arguments in the console

#### isBrowser Type:boolean

Checks if the current runtime JavaScript environment is in a browser context

#### noop() Return:void

The no-operation function, that returns void

#### now() Return:number

Returns an integer timestamp for the current time

#### _global() Return:object

Environment specific global object

`Contributing`

Wanna help? Cool! It will be really apreciated :)

You must add new test cases for any new feature or refactor you do, always following the same design/code patterns that already exist

Tests specs are completely written in Wisp language. Take a look to the language [documentation][wisp] if you are new with it. You should follow the Wisp language coding conventions

`$3`

Only node.js is required for development

Clone/fork this repository`$ git clone https://github.com/h2non/hu.git && cd hu`

Install package dependencies`$ npm install`

Compile code`$ make compile`

Run tests`$ make test`

Browser sources bundle generation`$ make browser`

Release a new version`$ make release``

License

Released under the MIT license

![Bitdeli Badge](https://bitdeli.com/free "Bitdeli Badge")

[wisp]: https://github.com/Gozala/wisp
[travis]: http://travis-ci.org/h2non/hu
[npm]: http://npmjs.org/package/hu