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Polyfill Lite for old browser

add Array.at and Object.hasOwn.

  1. // ==UserScript==
  2. // @name         Polyfill Lite for old browser
  3. // @namespace    github.com/hmjz100
  4. // @version      1.0.0
  5. // @description  add Array.at and Object.hasOwn.
  6. // @author       hmjz100
  7. // @match        *://*/*
  8. // @grant        none
  9. // ==/UserScript==
  10.  
  11. (function() {
  12.     'use strict';
  13.     if (!window.Array.prototype.at) {
  14.         window.Array.prototype.at = function(index) {
  15.             const len = this.length;
  16.             index = index >= 0 ? index : len + index;
  17.             if (index < 0 || index >= len) {
  18.                 return undefined;
  19.             }
  20.             return this[index];
  21.         };
  22.     }
  23.     if (!window.Object.hasOwn) {
  24.         window.Object.defineProperty(Object, 'hasOwn', {
  25.             value: function(object, key) {
  26.                 return Object.prototype.hasOwnProperty.call(object, key);
  27.             },
  28.             configurable: true,
  29.             enumerable: false,
  30.             writable: true
  31.         });
  32.     }
  33. })();