useful-iter

useful functions for working with Arrays and Objects

npm install useful-iter
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useful-iter

useful functions for working with Arrays and Objects

Installation

Install with component(1):

$ component install muigui/useful-iter

Install with npm:

$ npm install useful-iter

API

iter( item:Mixed ):Boolean

Returns true if the passed item can be iterated over.

iter.aggregate( item:Mixed, accumulator:Mixed, iterator:Function[, context:Object] ):Mixed

Works similar to Array.prototype.reduce.

Unlike reduce, you can also supply an optional context Object to aggregate.

aggregate will work on any iterable Object, so Array, Arguments, Function, HTMLCollection, NodeList, Object, etc.

If no context Object is supplied, the item being iterated over will be used as the context Object.

The iterator Function will receive 5 arguments:

argumenttypedescription
accumulatorWhen the iterator Function is first called, this will be the initially supplied accumulator, after which it will be previous value returned by the iterator Function.
valueThe current item in the iteration.
index_or_keyThe current index:Number or key:String corresponding to the current value in the iteration.
itemThe item being iterated over.

Example:


    var iter = require( 'useful-iter' );

    iter.aggregate( { one : 1, two : 2, three : 3 }, [], function( accumulator, value, key ) {
        accumulator.push( key );
        return accumulator;
    } ); // returns => ['one', 'two', 'three'];

    iter.aggregate( { one : 1, two : 2, three : 3 }, 1, function( accumulator, value, key ) {
        return accumulator += value;
    } ); // returns => 7;

    iter.aggregate( iter.range( 0, 10 ), 0, function( accumulator, value, index ) {
        return accumulator += ( value * index );
    } ); // returns => 385;

iter.equal( a:Array|Object, b:Array|Object ):Boolean

Returns true if both a and b deeply equal each other, false otherwise.

Example:


    var copy = require( 'useful-copy' ),
        iter = require( 'useful-iter' );

    var foo = { one : 1, two : 2, three : 3 },
        bar = copy( {}, foo );

    iter.equal( foo, bar ); // returns => true

    bar.four = 4;

    iter.equal( foo, bar ); // returns => false

iter.invoke( items:Array, method:String[, arg1:Mixed, arg2:Mixed, ..., argN:Mixed] ):Array

Executes the passed methodNOTE: method is a String, and should be the name of method that exists on each item in the Array — passing any extra arguments to each method call.

Example:


    iter.invoke( ['lorem', 'ipsum', 'dolor', 'sit', 'amet'], 'toUpperCase' ); // returns => ["LOREM", "IPSUM", "DOLOR", "SIT", "AMET"]

    iter.invoke( [1, 2, 3, 4, 5, 6, 7, 8] 'toString', 2 );                    // returns => ['1', '10', '11', '100', '101', '110', '111', '1000']

iter.len( item:Mixed ):Number

Tries the returns the length property of the passed item.

Example:


    var iter = require( 'useful-iter' );

    iter.len( { one : 1, two : 2, three : 3 } ); // returns => 3

    iter.len( [1, 2, 3] );                       // returns => 3

    iter.len( 'foobar' );                        // returns => 6

    iter.len( { one : 1, two : 2, three : 3 } ) === Object.keys( { one : 1, two : 2, three : 3 } ).length
    // returns => true

iter.pluck( items:Array, key:String[, only_existing:Boolean] ):Array

Returns a new Array where all the items are the values of the passed property key.

If only_existing is set to true then all null and undefined values will be omitted from the returned Array.

NOTEL if you want to get at properties deeper than one level down, you can simply supply the.correct.path.

Example:


    var data = [{ data : { value : 'foo' } }, { data : { value : 'bar' } }, {}, { value : 'blim' }, { data : { value : 'blam' } }];

    // harder to read
    iter.pluck( iter.pluck( data, 'data' ), 'value' ); // returns => ["foo", "bar", undefined, undefined, "blam"]

    // easier on the eye
    iter.pluck( data, 'data.value' );                  // returns => ["foo", "bar", undefined, undefined, "blam"]

    // return only existing values
    iter.pluck( data, 'data.value', true );            // returns => ["foo", "bar", "blam"]

iter.range( begin:Number|String, end:Number|String ):Array

Returns an Array starting at begin where each value is incremented by 1 until end is reached.

Example:


    var iter = require( 'useful-iter' );

    iter.range(  1,   10 );  // returns => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
    iter.range( 20, 1000 );  // returns => [20, 21, 22, ..., 1000]

    iter.range( 'A', 'z' );  // returns => ['A', 'B', 'C', ..., 'x', 'y', 'z']
    iter.range( 'α', 'ω' ); // returns => ['α', 'β', 'γ', ..., 'χ', 'ψ', 'ω']

NOTE: Only the first character will be incremented in a String range.

iter.remove( item:Array, value_or_index1:Number|Mixed|Number[]|Mixed[][, value_or_index2:Number|Mixed, ..., value_or_indexN:Number|Mixed] ):item

iter.remove( item:Object, property1:String|String[][, property2:String, ..., propertyN:String] ):item

Removes items from the passed Array or Object and returns the passed Array or Object.

If removing items from an Array, you can either pass the index of the item you want to remove or the item itself. If removing items from an Object, you simply pass the key of the item you want to remove.

Example:


    var iter = require( 'useful-iter' );

    var foo_arr = ['one', 'two', 'three'],
       foo_obj = { one : 1, two : 2, three : 3 };

    iter.remove( foo_arr, 'one', 'three' );   // returns => ['two']

    iter.remove( foo_arr, ['one', 'three'] ); // same as above

    iter.remove( foo_arr, 0, 2 );             // same as above

    iter.remove( foo_arr, [0, 2] );           // same as above

    iter.remove( foo_obj, 'one', 'three' );   // returns => { two : 2 }

    iter.remove( foo_obj, ['one', 'three'] ); // same as above

License

(The MIT License)

Copyright (c) 2011 christos "constantology" constandinou http://muigui.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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