25 lines
798 B
JavaScript
25 lines
798 B
JavaScript
|
'use strict';
|
||
|
|
|
||
|
|
var $TypeError = require('es-errors/type');
|
||
|
|
|
||
|
|
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 $strSlice = callBound('String.prototype.slice');
|
||
|
|
|
||
|
|
// https://262.ecma-international.org/9.0/#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' + $strSlice('0000' + $toLowerCase($numberToString(n, 16)), -4);
|
||
|
|
};
|