securityos/node_modules/es-abstract/2016/UTF16Encoding.js

26 lines
698 B
JavaScript

'use strict';
var GetIntrinsic = require('get-intrinsic');
var $TypeError = require('es-errors/type');
var $fromCharCode = GetIntrinsic('%String.fromCharCode%');
var floor = require('./floor');
var modulo = require('./modulo');
var isCodePoint = require('../helpers/isCodePoint');
// https://262.ecma-international.org/7.0/#sec-utf16encoding
module.exports = function UTF16Encoding(cp) {
if (!isCodePoint(cp)) {
throw new $TypeError('Assertion failed: `cp` must be >= 0 and <= 0x10FFFF');
}
if (cp <= 65535) {
return $fromCharCode(cp);
}
var cu1 = floor((cp - 65536) / 1024) + 0xD800;
var cu2 = modulo(cp - 65536, 1024) + 0xDC00;
return $fromCharCode(cu1) + $fromCharCode(cu2);
};