| 12345678910111213141516171819202122232425262728293031323334353637383940414243 | 'use strict';var $ = require('../internals/export');var toObject = require('../internals/to-object');var lengthOfArrayLike = require('../internals/length-of-array-like');var setArrayLength = require('../internals/array-set-length');var deletePropertyOrThrow = require('../internals/delete-property-or-throw');var doesNotExceedSafeInteger = require('../internals/does-not-exceed-safe-integer');// IE8-var INCORRECT_RESULT = [].unshift(0) !== 1;// V8 ~ Chrome < 71 and Safari <= 15.4, FF < 23 throws InternalErrorvar SILENT_ON_NON_WRITABLE_LENGTH = !function () {  try {    // eslint-disable-next-line es/no-object-defineproperty -- safe    Object.defineProperty([], 'length', { writable: false }).unshift();  } catch (error) {    return error instanceof TypeError;  }}();// `Array.prototype.unshift` method// https://tc39.es/ecma262/#sec-array.prototype.unshift$({ target: 'Array', proto: true, arity: 1, forced: INCORRECT_RESULT || SILENT_ON_NON_WRITABLE_LENGTH }, {  // eslint-disable-next-line no-unused-vars -- required for `.length`  unshift: function unshift(item) {    var O = toObject(this);    var len = lengthOfArrayLike(O);    var argCount = arguments.length;    if (argCount) {      doesNotExceedSafeInteger(len + argCount);      var k = len;      while (k--) {        var to = k + argCount;        if (k in O) O[to] = O[k];        else deletePropertyOrThrow(O, to);      }      for (var j = 0; j < argCount; j++) {        O[j] = arguments[j];      }    } return setArrayLength(O, len + argCount);  }});
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