bluebird/js/zalgo/filter.js

Full featured Promises/A+ implementation with exceptionally good performance

/**
 * Copyright (c) 2013 Petka Antonov
 * 
 * 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:</p>
 * 
 * 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.
 */
"use strict";
module.exports = function( Promise, Promise$_All ) {

    var errors = require( "./errors.js");
    var apiRejection = errors.apiRejection;
    var PromiseArray = require( "./promise_array.js" );
    var ASSERT = require( "./assert.js" );

    function Promise$_filterer( fulfilleds ) {
        var fn = this;
        var receiver = void 0;
        if( typeof fn !== "function" )  {
            receiver = fn.receiver;
            fn = fn.fn;
        }
        var ret = new Array( fulfilleds.length );
        var j = 0;
        if( receiver === void 0 ) {
             for( var i = 0, len = fulfilleds.length; i < len; ++i ) {
                var item = fulfilleds[i];
                if( item === void 0 &&
                    !( i in fulfilleds ) ) {
                    continue;
                }
                if( fn( item, i, len ) ) {
                    ret[j++] = item;
                }
            }
        }
        else {
            for( var i = 0, len = fulfilleds.length; i < len; ++i ) {
                var item = fulfilleds[i];
                if( item === void 0 &&
                    !( i in fulfilleds ) ) {
                    continue;
                }
                if( fn.call( receiver, item, i, len ) ) {
                    ret[j++] = item;
                }
            }
        }
        ret.length = j;
        return ret;
    }

    function Promise$_Filter( promises, fn, useBound, caller ) {
        if( typeof fn !== "function" ) {
            return apiRejection( "fn is not a function" );
        }

        if( useBound === true ) {
            fn = {
                fn: fn,
                receiver: promises._boundTo
            };
        }

        return Promise$_All( promises, PromiseArray, caller,
                useBound === true ? promises._boundTo : void 0 )
            .promise()
            ._then( Promise$_filterer, void 0, void 0, fn, void 0, caller );
    }

    Promise.filter = function Promise$Filter( promises, fn ) {
        return Promise$_Filter( promises, fn, false, Promise.filter );
    };

    Promise.prototype.filter = function Promise$filter( fn ) {
        return Promise$_Filter( this, fn, true, this.filter );
    };
};