functioner

A Node.js module containing a set of higher order functions

functioner is a library mainly focused on higher-order functions, like the map, filter, and forEach functions used on arrays.

This functional programming methodology can be more easily embraced with a large set of higher-order functions allowing more compact anonymous function creation.

functioner contains a set of assertion functions, a lot like other libraries; however, these functions are higher-order which allows for unique usage in modules like dependon.

Install

$ npm install functioner

Usage

assert

var f = require('functioner').assert;

var numbers = [0, 1, 2, 3, 4, 5];

var lessThan3 = numbers.filter(f.lessThan(3));
//    => [ 0, 1, 2 ]

var odds = numbers.filter(f.odd);
//    => [1, 3, 5]

var between1and4 = numbers.filter(f.between(1, 4));
//    => [2, 3]

var types = [1, 'abc', {}, [1,2,3], false];

var iters = types.filter(f.type('iterable'));
//    => [ 'abc', [ 1, 2, 3 ] ]

• type(string): returns a function that checks the types variables given to the function.
• greaterThan(number): returns a function that checks if a number is greater than the original number given.
• gt(number): short notation for greaterThan
• greaterThanOrEqualTo(number): returns a function that checks if a number is greater than or equal to the original number given.
• gte(number): short notation for greaterThanOrEqualTo
• lessThan(number): returns a function that checks if a number is less than the original number given.
• lt(number): short notation for lessThan
• lessThanOrEqualTo(number): returns a function that checks if a number is less than or equal to the original number given.
• lte(number): short notation for lessThanOrEqualTo
• equalTo(value): returns a function that checks if a given value is equal to the original.
• eq(value): short notation for equalTo
• null(value): returns true if value equals null, false otherwise.
• undefined(value): returns true if value equals undefined, false otherwise.
• assigned(value): returns true if value does not equal undefined, false otherwise.
• has(prop): returns a function that returns true if a given object has the property initially given.
• includes(value): returns a function that returns true if a given array has the value initially specified.
• contains(substring): returns a function that returns true if a given string has the substring initially given.
• match(regex): returns a function that returns true if a given string matches a given regular expression.
• positive(number): returns true if value is greater than 0, false otherwise.
• negative(number): returns true if value is less than 0, false otherwise.
• zero(number): returns true if value is equal to 0, false otherwise.
• infinity(number): returns true if value is equal to Infinity, false otherwise.
• finite(number): returns true if value is not equal to Infinity, false otherwise.
• between(number, number): returns a function that returns true, if a given value is between the two numbers initially given.
• even(number): returns true if value is even, false otherwise.
• odd(number): returns true if value is odd, false otherwise.

math

var f = require('functioner').math;

var numbers = [0, 1, 2, 3, 4];

var add2 = numbers.map(f.add(2));
//    => [2, 3, 4, 5, 6]

var clamped = numbers.map(f.clamp(1, 3));
//    => [ 1, 1, 2, 3, 3 ]

var scaled = numbers.map(f.scale(0, 4, 0, 1));
//    => [ 0, 0.25, 0.5, 0.75, 1 ]

• add(number): returns a function that adds the number given to any value given to the function.
• subtract(number): returns a function that subtracts the number given to any value given to the function.
• divide(number): returns a function that divides any number given to the function by the number initially given.
• multiply(number): returns a function that multiplies any number given to the function by the number initially given.
• pow(number): returns a function that takes the power of any number given to the function to the exponent of the number initially given.
• sum(function): takes a function and returns a function that calculates the sum from the given parameters from n0 to n
• scale(inMin, inMax, outMin, outMax): returns a function that scales a the number given, according to the in range and out range.
• clamp(min, max): returns a function that clamps the value given in the range initially given.
• compose(...functions): returns a function composed of all the functions given, like so: f0(f1(f2(fn)))

extras

• accessor(string): returns a function that gives the value at an objects has. Example: accessor('length')(str) would return the length of str.
• index(integer): returns a function that returns the index given of a given array.
• print(value): console.log(value)