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Ankrat/[].every()_polyfill.js

Last active June 13, 2016 14:45
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  1. Ankrat revised this gist Jun 13, 2016. No changes.
  2. Ankrat renamed this gist Jun 13, 2016. 1 changed file with 0 additions and 0 deletions.
    0 [].every() polyfill → [].every()_polyfill.js
    View file
    File renamed without changes.
  3. Ankrat created this gist Jun 13, 2016.
    63 changes: 63 additions & 0 deletions [].every() polyfill
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,63 @@
    if (!Array.prototype.every) {
    Array.prototype.every = function(callbackfn, thisArg) {
    'use strict';
    var T, k;

    if (this == null) {
    throw new TypeError('this is null or not defined');
    }

    // 1. Let O be the result of calling ToObject passing the this
    // value as the argument.
    var O = Object(this);

    // 2. Let lenValue be the result of calling the Get internal method
    // of O with the argument "length".
    // 3. Let len be ToUint32(lenValue).
    var len = O.length >>> 0;

    // 4. If IsCallable(callbackfn) is false, throw a TypeError exception.
    if (typeof callbackfn !== 'function') {
    throw new TypeError();
    }

    // 5. If thisArg was supplied, let T be thisArg; else let T be undefined.
    if (arguments.length > 1) {
    T = thisArg;
    }

    // 6. Let k be 0.
    k = 0;

    // 7. Repeat, while k < len
    while (k < len) {

    var kValue;

    // a. Let Pk be ToString(k).
    // This is implicit for LHS operands of the in operator
    // b. Let kPresent be the result of calling the HasProperty internal
    // method of O with argument Pk.
    // This step can be combined with c
    // c. If kPresent is true, then
    if (k in O) {

    // i. Let kValue be the result of calling the Get internal method
    // of O with argument Pk.
    kValue = O[k];

    // ii. Let testResult be the result of calling the Call internal method
    // of callbackfn with T as the this value and argument list
    // containing kValue, k, and O.
    var testResult = callbackfn.call(T, kValue, k, O);

    // iii. If ToBoolean(testResult) is false, return false.
    if (!testResult) {
    return false;
    }
    }
    k++;
    }
    return true;
    };
    }