levenshtein.js 2.3 KB

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  1. "use strict";
  2. /*
  3. Copyright (c) 2011 Andrei Mackenzie
  4. Permission is hereby granted, free of charge, to any person obtaining a copy of
  5. this software and associated documentation files (the "Software"), to deal in
  6. the Software without restriction, including without limitation the rights to
  7. use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
  8. the Software, and to permit persons to whom the Software is furnished to do so,
  9. subject to the following conditions:
  10. The above copyright notice and this permission notice shall be included in all
  11. copies or substantial portions of the Software.
  12. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  13. IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  14. FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
  15. COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  16. IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  17. CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  18. */
  19. Object.defineProperty(exports, "__esModule", { value: true });
  20. exports.levenshtein = void 0;
  21. // levenshtein distance algorithm, pulled from Andrei Mackenzie's MIT licensed.
  22. // gist, which can be found here: https://gist.github.com/andrei-m/982927
  23. // Compute the edit distance between the two given strings
  24. function levenshtein(a, b) {
  25. if (a.length === 0)
  26. return b.length;
  27. if (b.length === 0)
  28. return a.length;
  29. const matrix = [];
  30. // increment along the first column of each row
  31. let i;
  32. for (i = 0; i <= b.length; i++) {
  33. matrix[i] = [i];
  34. }
  35. // increment each column in the first row
  36. let j;
  37. for (j = 0; j <= a.length; j++) {
  38. matrix[0][j] = j;
  39. }
  40. // Fill in the rest of the matrix
  41. for (i = 1; i <= b.length; i++) {
  42. for (j = 1; j <= a.length; j++) {
  43. if (b.charAt(i - 1) === a.charAt(j - 1)) {
  44. matrix[i][j] = matrix[i - 1][j - 1];
  45. }
  46. else {
  47. matrix[i][j] = Math.min(matrix[i - 1][j - 1] + 1, // substitution
  48. Math.min(matrix[i][j - 1] + 1, // insertion
  49. matrix[i - 1][j] + 1)); // deletion
  50. }
  51. }
  52. }
  53. return matrix[b.length][a.length];
  54. }
  55. exports.levenshtein = levenshtein;