extendscript-es5-shim/Array/every.js

a collection of useful es5-shims for Extendscript

/*
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every
*/
if (!Array.prototype.every) {
  Array.prototype.every = function(callback, thisArg) {
    var T, k;

    if (this === void 0 || this === null) {
      throw new TypeError('Array.prototype.every called on null or undefined');
    }

    // 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(callback) is false, throw a TypeError exception.
    if (callback.__class__ !== 'Function') {
      throw new TypeError(callback + ' is not a function');
    }

    // 5. If thisArg was supplied, let T be thisArg; else let T be undefined.
    T = (arguments.length > 1) ? thisArg : void 0;

    // 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 callback with T as the this value and argument list 
        //     containing kValue, k, and O.
        var testResult = callback.call(T, kValue, k, O);

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