Enumerable.js

utility functions for all types of collections

When you use a JavaScript array or hash table, you have so many ways to get utility functions at your disposal through libraries like Underscore, Zepto, jQuery, or natively in ECMAScript5. Why can't we have these same utility functions just as easily for other data structures that can be iterated over? Say, a linked list, or a tree, or a graph, or that newest thing that your monkey came up with?

This library is heavily inspired by Ruby's Enumerable module, and borrows great deal of its functionality.

Note: This is not meant to be a standalone library, but to be used in conjunction with another data type that has a defineable .each method.

Quickstart

1. Have a collection of some sort

// contrived example
var LinkedList = function(){
  this.head = null;
  this.tail = null;
};
 
LinkedList.prototype.add = function(value){
  var node = {
    value: value,
    next: null
  };
  if(!this.head){
    this.head = this.tail = node;
  } else {
    this.tail.next = node;
    this.tail = node;
  }
};
 

2. Extend that thing with enumerable

// option 1: use enumerable.extend
enumerable.extend(LinkedList.prototype);
 
// option 2: use Object#create. NOTE: In this case, doing so will will completely 
// reassign what LinkedList.prototype is. Here, we would need to define 
// LinkedList#add again after this.
 
LinkedList.prototype = Object.create(enumerable);

3. Define what .each means

LinkedList.prototype.each = function(callback, context){
  var node = this.head;
  while(node){
    callback.call(context, node);
    node = node.next;
  }
};

4. Stand in awe of all the awesome utility functions you suddenly have

var list = new LinkedList();
list.add(5);
list.add(9);
list.add(15);
 
var sum = list.reduce(function(sum, node){ return sum + node.value; }, 0);
console.log(sum);
// => 27   ¯\_(ツ)_/¯

Supported functions

Returns a unit of the collection

• first
• max
• min
• detect
• find

Returns as specified

• reduce / inject / foldl

Returns an array

• filter / select / findAll
• mapToArray
• toArray
• sort
• partition

Returns this

• mapInPlace
• eachCons
• eachUntilN
• eachSlice
• reverseEach
• cycle

Returns an integer

• count

Returns a boolean

• all
• any
• none
• hasN

Installation

As an NPM module npm install enumerablejs

As a bower module bower install enumerablejs

From Github git clone git@github.com:bioball/Enumerable.js.git

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*This is currently a work in progress. Please send in pull requests! However, please also have test coverage in your pull requests.