int-8-array.polyfill.js

/**
 * Int8Array.prototype.from
 * version 0.0.0
 * Browser Compatibility:
 * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/from#browser_compatibility
 */
if (!Int8Array.prototype.from) {
  Int8Array.prototype.from = function (obj, func, thisObj) {

    var typedArrayClass = Int8Array.prototype;
    if (typeof this !== 'function') {
      throw new TypeError('# is not a constructor');
    }
    if (this.prototype !== typedArrayClass) {
      throw new TypeError('this is not a typed array.');
    }

    func = func || function (elem) {
      return elem;
    };

    if (typeof func !== 'function') {
      throw new TypeError('specified argument is not a function');
    }

    obj = Object(obj);
    if (!obj['length']) {
      return new this(0);
    }
    var copy_data = [];
    for (var i = 0; i < obj.length; i++) {
      copy_data.push(obj[i]);
    }

    copy_data = copy_data.map(func, thisObj);

    var typed_array = new this(copy_data.length);
    for (var i = 0; i < typed_array.length; i++) {
      typed_array[i] = copy_data[i];
    }
    return typed_array;
  };
}