udemy-react/02/node_modules/js-levenshtein/index.js

'use strict';
module.exports = (function()
{
  function _min(d0, d1, d2, bx, ay)
  {
    return d0 < d1 || d2 < d1
        ? d0 > d2
            ? d2 + 1
            : d0 + 1
        : bx === ay
            ? d1
            : d1 + 1;
  }

  return function(a, b)
  {
    if (a === b) {
      return 0;
    }

    if (a.length > b.length) {
      var tmp = a;
      a = b;
      b = tmp;
    }

    var la = a.length;
    var lb = b.length;

    while (la > 0 && (a.charCodeAt(la - 1) === b.charCodeAt(lb - 1))) {
      la--;
      lb--;
    }

    var offset = 0;

    while (offset < la && (a.charCodeAt(offset) === b.charCodeAt(offset))) {
      offset++;
    }

    la -= offset;
    lb -= offset;

    if (la === 0 || lb < 3) {
      return lb;
    }

    var x = 0;
    var y;
    var d0;
    var d1;
    var d2;
    var d3;
    var dd;
    var dy;
    var ay;
    var bx0;
    var bx1;
    var bx2;
    var bx3;

    var vector = [];

    for (y = 0; y < la; y++) {
      vector.push(y + 1);
      vector.push(a.charCodeAt(offset + y));
    }

    var len = vector.length - 1;

    for (; x < lb - 3;) {
      bx0 = b.charCodeAt(offset + (d0 = x));
      bx1 = b.charCodeAt(offset + (d1 = x + 1));
      bx2 = b.charCodeAt(offset + (d2 = x + 2));
      bx3 = b.charCodeAt(offset + (d3 = x + 3));
      dd = (x += 4);
      for (y = 0; y < len; y += 2) {
        dy = vector[y];
        ay = vector[y + 1];
        d0 = _min(dy, d0, d1, bx0, ay);
        d1 = _min(d0, d1, d2, bx1, ay);
        d2 = _min(d1, d2, d3, bx2, ay);
        dd = _min(d2, d3, dd, bx3, ay);
        vector[y] = dd;
        d3 = d2;
        d2 = d1;
        d1 = d0;
        d0 = dy;
      }
    }

    for (; x < lb;) {
      bx0 = b.charCodeAt(offset + (d0 = x));
      dd = ++x;
      for (y = 0; y < len; y += 2) {
        dy = vector[y];
        vector[y] = dd = _min(dy, d0, dd, bx0, vector[y + 1]);
        d0 = dy;
      }
    }

    return dd;
  };
})();