Description

A package of functions that extend array functionality in Node

Installation

npm install arrayhelper

Usage

Just add the following line and the Array.prototype will then include all Functions

require('arrayhelper');

Functions

Array.prototype.distinct()

Description

Returns an array with duplicate items removes

Returns

Array

Example

var arr = [1,1,5,6,3,5,6,7,7];
var distinct = arr.distinct();
console.log(distinct); //[ 1, 5, 6, 3, 7 ]

Array.prototype.equals(arr)

Description

Returns true if elements in the two arrays are equal, false otherwise. Also checks for nested arrays and their equality.

Parameters

arr - Array to compare with. Returns false if this is not an array

Returns

boolean, true if elements in the arrays are equal

Example

var arr1 = [ 1, 2, [ 3, 4 ] ];
var arr2 = [ 1, 2, [ 3, 4 ] ];
var arr3 = [ 1, 2, 3, 4 ];

console.log(arr1.equals(arr2)); //true
console.log(arr1.equals(arr3)); //false

Array.prototype.toDict(key)

Description

Converts an array of objects into an object with keys specified by key

Parameters

key - String. The value from the objects to use as the key in the dictionary

Returns

Object

Example

var arr = [
    { ID: 1, Data: 'hello world' },
    { ID: 2, Data: 'arrays are useful', Data2: 'dictionaries are good to' },
    { ID: 2, Data: 'example'}
];
console.log(arr.toDict('ID'));
/*
 * { '1': { ID: 1, Data: 'hello world' },
 *   '2':
 *   [ { ID: 2,
 *       Data: 'arrays are useful',
 *       Data2: 'dictionaries are good to' },
 *     { ID: 2, Data: 'example' } ] } 
 */

 console.log(arr.toDict('Data'));
 /*
  * { 'hello world': { ID: 1, Data: 'hello world' },
  * 'arrays are useful':
  *  { ID: 2,
  *    Data: 'arrays are useful',
  *    Data2: 'dictionaries are good to' },
  * example: { ID: 2, Data: 'example' } }
  */

  console.log(arr.toDict('ID')[1]); //{ ID: 1, Data: 'hello world' }
  console.log(arr.toDict('Data').example); //{ ID: 2, Data: 'example' }

Array.prototype.forEachCallback(callback, [end])

Description

Loops through each item in the array and waits (non blocking) for the callback before proceeding to the next item in the array.

Parameters

callback - function(item, next) item - the current item in the array next - call when finished to move to the next item in the array

end - function. Optional. Called when the for each loop is complete

Returns

No return value

example

var arr = [
    { ID: 1, Data: 'foo' },
    { ID: 2, Data: 'bar' }
];

arr.forEachCallback(function(item, next) {
    db.someCallToDb(item, function(err, res) {
        next();
    });
}, function() {
    console.log('Loop complete notify client side');
});

Array.prototype.execute([callback])

Description

Executes an array of functions in a semi-async manner. Does not execute the callback untill all functions are complete. Each function in the array accepts one variable that is a function to call when execution is complete.

Useful for when you want to make multiple calls to a database and not have to wait for each one before executing the next.

Each function in the array is in the below format

function(done) {

}

Where done is the callback in the format function(err). If err is set other functions in the array may finish executing but no more are started and execution drops straight out to the callback supplied in the execute call.

See example for details.

Parameters

callback - function(err). Optional. Called when all functions have finished execution. err - set if there was an error returned from on of the functions in the array

Returns

No return value

Example

[
    function(done) {
        console.log('function 1');
        done();
    },
    function(done) {
        done(new Error('Error at function 2'));
    },
    function(done) {
        console.log('function 3');
        done();
    }
].execute(function(err) {
    if(err) console.log(err);
    console.log('Execution complete');
});

/* outputs
 * function 1
 * function 3
 * [Error: Error at function 2]
 * Execution complete
 */