npm install huhu 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.
- 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
#### 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`
!Chrome | !Firefox | !IE | !Opera | !Safari
--- | --- | --- | --- | --- |
+5 | +3.5 | +9 | +10.6 | +5 |
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.
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
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.
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.
- 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
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
#### 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
#### 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
#### 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
#### 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]
#### 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}}}
#### 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]
#### 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
#### 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
#### 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
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
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
Copyright (c) Tomas Aparicio
Released under the MIT license

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