UTF16Encoding.js 671 B

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  1. 'use strict';
  2. var GetIntrinsic = require('../GetIntrinsic');
  3. var $TypeError = GetIntrinsic('%TypeError%');
  4. var $fromCharCode = GetIntrinsic('%String.fromCharCode%');
  5. var floor = require('./floor');
  6. var modulo = require('./modulo');
  7. // https://ecma-international.org/ecma-262/7.0/#sec-utf16encoding
  8. module.exports = function UTF16Encoding(cp) {
  9. if (typeof cp !== 'number' || cp < 0 || cp > 0x10FFFF) {
  10. throw new $TypeError('Assertion failed: `cp` must be >= 0 and <= 0x10FFFF');
  11. }
  12. if (cp <= 65535) {
  13. return cp;
  14. }
  15. var cu1 = floor((cp - 65536) / 1024) + 0xD800;
  16. var cu2 = modulo(cp - 65536, 1024) + 0xDC00;
  17. return $fromCharCode(cu1) + $fromCharCode(cu2);
  18. };