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							- '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 InternalError
 
- var properErrorOnNonWritableLength = function () {
 
-   try {
 
-     // eslint-disable-next-line es/no-object-defineproperty -- safe
 
-     Object.defineProperty([], 'length', { writable: false }).unshift();
 
-   } catch (error) {
 
-     return error instanceof TypeError;
 
-   }
 
- };
 
- var FORCED = INCORRECT_RESULT || !properErrorOnNonWritableLength();
 
- // `Array.prototype.unshift` method
 
- // https://tc39.es/ecma262/#sec-array.prototype.unshift
 
- $({ target: 'Array', proto: true, arity: 1, forced: FORCED }, {
 
-   // 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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