extendscript-es5-shim/Array/filter.js

a collection of useful es5-shims for Extendscript

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

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

    var t = Object(this);
    var len = t.length >>> 0;

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

    var res = [];

    var T = (arguments.length > 1) ? thisArg : void 0;
    
    for (var i = 0; i < len; i++) {
      if (i in t) {
        var val = t[i];

        // NOTE: Technically this should Object.defineProperty at
        //       the next index, as push can be affected by
        //       properties on Object.prototype and Array.prototype.
        //       But that method's new, and collisions should be
        //       rare, so use the more-compatible alternative.
        if (callback.call(T, val, i, t)) {
          res.push(val);
        }
      }
    }

    return res;
  };
}