_stringSize.js 1.7 KB

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  1. var reHasComplexSymbol = require('./_reHasComplexSymbol');
  2. /** Used to compose unicode character classes. */
  3. var rsAstralRange = '\\ud800-\\udfff',
  4. rsComboMarksRange = '\\u0300-\\u036f\\ufe20-\\ufe23',
  5. rsComboSymbolsRange = '\\u20d0-\\u20f0',
  6. rsVarRange = '\\ufe0e\\ufe0f';
  7. /** Used to compose unicode capture groups. */
  8. var rsAstral = '[' + rsAstralRange + ']',
  9. rsCombo = '[' + rsComboMarksRange + rsComboSymbolsRange + ']',
  10. rsFitz = '\\ud83c[\\udffb-\\udfff]',
  11. rsModifier = '(?:' + rsCombo + '|' + rsFitz + ')',
  12. rsNonAstral = '[^' + rsAstralRange + ']',
  13. rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}',
  14. rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]',
  15. rsZWJ = '\\u200d';
  16. /** Used to compose unicode regexes. */
  17. var reOptMod = rsModifier + '?',
  18. rsOptVar = '[' + rsVarRange + ']?',
  19. rsOptJoin = '(?:' + rsZWJ + '(?:' + [rsNonAstral, rsRegional, rsSurrPair].join('|') + ')' + rsOptVar + reOptMod + ')*',
  20. rsSeq = rsOptVar + reOptMod + rsOptJoin,
  21. rsSymbol = '(?:' + [rsNonAstral + rsCombo + '?', rsCombo, rsRegional, rsSurrPair, rsAstral].join('|') + ')';
  22. /** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */
  23. var reComplexSymbol = RegExp(rsFitz + '(?=' + rsFitz + ')|' + rsSymbol + rsSeq, 'g');
  24. /**
  25. * Gets the number of symbols in `string`.
  26. *
  27. * @private
  28. * @param {string} string The string to inspect.
  29. * @returns {number} Returns the string size.
  30. */
  31. function stringSize(string) {
  32. if (!(string && reHasComplexSymbol.test(string))) {
  33. return string.length;
  34. }
  35. var result = reComplexSymbol.lastIndex = 0;
  36. while (reComplexSymbol.test(string)) {
  37. result++;
  38. }
  39. return result;
  40. }
  41. module.exports = stringSize;