vue hello world项目
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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 toIntegerOrInfinity = require('../internals/to-integer-or-infinity');
var addToUnscopables = require('../internals/add-to-unscopables');
// `Array.prototype.at` method
// https://github.com/tc39/proposal-relative-indexing-method
$({ target: 'Array', proto: true }, {
at: function at(index) {
var O = toObject(this);
var len = lengthOfArrayLike(O);
var relativeIndex = toIntegerOrInfinity(index);
var k = relativeIndex >= 0 ? relativeIndex : len + relativeIndex;
return (k < 0 || k >= len) ? undefined : O[k];
}
});
addToUnscopables('at');