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24 lines
868 B
24 lines
868 B
11 months ago
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'use strict';
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var $ = require('../internals/export');
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var uncurryThis = require('../internals/function-uncurry-this');
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var requireObjectCoercible = require('../internals/require-object-coercible');
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var toString = require('../internals/to-string');
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var charCodeAt = uncurryThis(''.charCodeAt);
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// `String.prototype.isWellFormed` method
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// https://github.com/tc39/proposal-is-usv-string
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$({ target: 'String', proto: true }, {
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isWellFormed: function isWellFormed() {
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var S = toString(requireObjectCoercible(this));
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var length = S.length;
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for (var i = 0; i < length; i++) {
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var charCode = charCodeAt(S, i);
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// single UTF-16 code unit
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if ((charCode & 0xF800) !== 0xD800) continue;
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// unpaired surrogate
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if (charCode >= 0xDC00 || ++i >= length || (charCodeAt(S, i) & 0xFC00) !== 0xDC00) return false;
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} return true;
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}
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});
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