YAEnumerable

Yet Another Enumerable Java Script Framework

Purpose

To create and maintain a linq type JS framework. See Credits/Other Frameworks for alternatives.

Install

npm install yaenumerable

Example

Each selector will at a minimum return an item and the index of the item. The index is always the last item returned in the callback. See tests for additional examples.

where Condition

var enumerable = require("yaenumerable");
var anArray = [{a:1},{a:2},{a:3}];
 
//aValues will now be [{a:2},{a:3}]
var aValues = enumerable.fromArray(anArray)
                        .where(function(item){return item.a > 1;})
                        .toArray();

select

var enumerable = require("yaenumerable");
var anArray = [{a:1},{a:2},{a:3}];
 
//aValues will now be [1,2,3]
var aValues = enumerable.fromArray(anArray)
                        .select( function(item){ return item.a; } )
                        .toArray();

selectMany

Allows you to flatten an array

var enumerable = require("yaenumerable");
var anArray = [ {a:[1,2,3]}, {a:[4,5,6]}, {a:[7,8,9]} ];
 
//Will return: [1,2,3,4,5,6,7,8,9]
var flattenedArray = enumerable.selectMany(function(item){return item.a})
                               .toArray();

first

var enumerable = require("yaenumerable");
var anArray = [{a:1},{a:2},{a:3}];
 
//if no function specified will return first item:{a:1}
var firstObject = enumerable.fromArray(anArray).first();
 
//Since function is specfied to return a, will return 1
var firstA = enumerable.fromArray(anArray)
                          .first(function(item){return item.a;});

sum

var enumerable = require("yaenumerable");
 
//sum without a selector
//In this case it will return 6
var sum = enumerable.fromArray([1,2,3]).sum();
 
//When specified with a selector will return the sum of that item:
//In this case it will return 6
var sumOfA = enumerable.fromArray([{a:1},{a:2},{a:3}])
                          .sum(function(item){return item.a;});

count

count items in enumerable. Example use is with an enumerable

var enumerable = require("yaenumerable");
var anArray = [1,2,3];
 
//Will return 2
var count = enumerable.fromArray([1,2,3])
                      .where(function(item){return item > 1;})
                      .count();

any

Determines if any items meet a condtion

var enumerable = require("yaenumerable");
var anArray = [1,2,3];
 
//Will return true
var hasItemGreaterThan1 = enumerable.fromArray([1,2,3])
                      .any(function(item){return item > 1;});
 
//Can use with a selector as well
var hasItemAGreaterThan1 = enumerable.fromArray([{a:1},{a:2},{a:3}])
                      .any(function(item){return item.a > 1;});
 

forEach

var enumerable = require("yaenumerable");
var anArray = [{a:1},{a:2},{a:3}];
 
//aValues will now be [1,2,3]
var aValues = enumerable.fromArray(anArray)
                        .forEach( function(item){/*Do something useful*/})
                        .toArray();

asyncForEach

Allows you to make async calls on each item in an array and get the results of all calls when each call is complete.

var enumerable = require("yaenumerable");
var anArray = [{a:1},{a:2},{a:3}];
 
  var longProcess = function(item, onLongProcessComplete){
  //Some long process
  var result = item;
  onLongProcessComplete(result);
  };
 
  enumerable.fromArray(anArray)
    			.asyncForEach(longProcess,
                        function(results){ 
                          //results is an array with each updated item
                          onComplete(results);
                        });

For additional examples see the tests. To run them:

npm test

Credits/Other Frameworks

• enumerablejs - lukesmith's very comprehensive framework
• enumerable - VisionMedia TJ Holowaychuk