| 'use strict'; |
| |
| var GetIntrinsic = require('get-intrinsic'); |
| |
| var $TypeError = GetIntrinsic('%TypeError%'); |
| |
| var callBound = require('call-bind/callBound'); |
| |
| var $charCodeAt = callBound('String.prototype.charCodeAt'); |
| var $numberToString = callBound('Number.prototype.toString'); |
| var $toLowerCase = callBound('String.prototype.toLowerCase'); |
| |
| var StringPad = require('./StringPad'); |
| |
| // https://262.ecma-international.org/11.0/#sec-unicodeescape |
| |
| module.exports = function UnicodeEscape(C) { |
| if (typeof C !== 'string' || C.length !== 1) { |
| throw new $TypeError('Assertion failed: `C` must be a single code unit'); |
| } |
| var n = $charCodeAt(C, 0); |
| if (n > 0xFFFF) { |
| throw new $TypeError('`Assertion failed: numeric value of `C` must be <= 0xFFFF'); |
| } |
| |
| return '\\u' + StringPad($toLowerCase($numberToString(n, 16)), 4, '0', 'start'); |
| }; |