bbo/byte_len.js

bbo is a utility library of zero dependencies for javascript.

'use strict';

/* eslint-disable */

/**
 * Returns the length of a string in bytes by Unicode (utf-8 utf8 utf-16 utf16)
 */
function byteLen(str, charset) {
  var total = 0;
  var charCode;

  if (charset === 'utf-8' || charset === 'utf8') {
    for (var i = 0, len = str.length; i < len; i++) {
      charCode = str.codePointAt(i);

      if (charCode <= 0x007f) {
        total += 1;
      } else if (charCode <= 0x07ff) {
        total += 2;
      } else if (charCode <= 0xffff) {
        total += 3;
      } else {
        total += 4;
        i++;
      }
    }
  } else if (charset === 'utf-16' || charset === 'utf16') {
    for (var _i = 0, _len = str.length; _i < _len; _i++) {
      charCode = str.codePointAt(_i);

      if (charCode <= 0xffff) {
        total += 2;
      } else {
        total += 4;
        _i++;
      }
    }
  } else {
    total = str.replace(/[^\x00-\xff]/g, 'aa').length;
  }

  return total;
}

module.exports = byteLen;