28 lines
831 B
JavaScript
28 lines
831 B
JavaScript
'use strict';
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var GetIntrinsic = require('../GetIntrinsic');
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var $TypeError = GetIntrinsic('%TypeError%');
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var callBound = require('../helpers/callBound');
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var $charCodeAt = callBound('String.prototype.charCodeAt');
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var $numberToString = callBound('Number.prototype.toString');
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var $toLowerCase = callBound('String.prototype.toLowerCase');
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var StringPad = require('./StringPad');
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// https://tc39.es/ecma262/2020/#sec-unicodeescape
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module.exports = function UnicodeEscape(C) {
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if (typeof C !== 'string' || C.length !== 1) {
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throw new $TypeError('Assertion failed: `C` must be a single code unit');
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}
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var n = $charCodeAt(C, 0);
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if (n > 0xFFFF) {
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throw new $TypeError('`Assertion failed: numeric value of `C` must be <= 0xFFFF');
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}
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return '\\u' + StringPad($toLowerCase($numberToString(n, 16)), 4, '0', 'start');
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};
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