levenshtein.js 1.0 KB

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  1. export function levenshtein(a, b) {
  2. if (a.length === 0)
  3. return b.length;
  4. if (b.length === 0)
  5. return a.length;
  6. const matrix = [];
  7. let i;
  8. for (i = 0; i <= b.length; i++) {
  9. matrix[i] = [i];
  10. }
  11. let j;
  12. for (j = 0; j <= a.length; j++) {
  13. matrix[0][j] = j;
  14. }
  15. for (i = 1; i <= b.length; i++) {
  16. for (j = 1; j <= a.length; j++) {
  17. if (b.charAt(i - 1) === a.charAt(j - 1)) {
  18. matrix[i][j] = matrix[i - 1][j - 1];
  19. }
  20. else {
  21. if (i > 1 &&
  22. j > 1 &&
  23. b.charAt(i - 2) === a.charAt(j - 1) &&
  24. b.charAt(i - 1) === a.charAt(j - 2)) {
  25. matrix[i][j] = matrix[i - 2][j - 2] + 1;
  26. }
  27. else {
  28. matrix[i][j] = Math.min(matrix[i - 1][j - 1] + 1, Math.min(matrix[i][j - 1] + 1, matrix[i - 1][j] + 1));
  29. }
  30. }
  31. }
  32. }
  33. return matrix[b.length][a.length];
  34. }