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27 lines
1.1 KiB
27 lines
1.1 KiB
var toInteger = require('../internals/to-integer'); |
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var requireObjectCoercible = require('../internals/require-object-coercible'); |
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// `String.prototype.{ codePointAt, at }` methods implementation |
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var createMethod = function (CONVERT_TO_STRING) { |
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return function ($this, pos) { |
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var S = String(requireObjectCoercible($this)); |
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var position = toInteger(pos); |
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var size = S.length; |
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var first, second; |
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if (position < 0 || position >= size) return CONVERT_TO_STRING ? '' : undefined; |
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first = S.charCodeAt(position); |
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return first < 0xD800 || first > 0xDBFF || position + 1 === size |
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|| (second = S.charCodeAt(position + 1)) < 0xDC00 || second > 0xDFFF |
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? CONVERT_TO_STRING ? S.charAt(position) : first |
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: CONVERT_TO_STRING ? S.slice(position, position + 2) : (first - 0xD800 << 10) + (second - 0xDC00) + 0x10000; |
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}; |
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}; |
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module.exports = { |
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// `String.prototype.codePointAt` method |
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// https://tc39.github.io/ecma262/#sec-string.prototype.codepointat |
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codeAt: createMethod(false), |
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// `String.prototype.at` method |
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// https://github.com/mathiasbynens/String.prototype.at |
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charAt: createMethod(true) |
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};
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