A (node|common).js module implementation of the Levenshtein Distance Algorithm

levenshtein.js

// module for calculating the Levenshtein distance between 2 strings

// a matrix to hold the distances
var d = [],
// reusable lengths of the passed in words
lenOne, lenTwo,
// counters
i,j,
// temp equality check
eq;

exports.distance = function(one, two) {
    lenOne = one.length;
    lenTwo = two.length;

    // filling along the y axis, 
    // NOTE: <= operator to retain the initial 0
    for (i = 0; i <= lenOne; i++) {
	// start an array at each char of word one
	d[i] = [];
	// numeric count of each char beyond 0
	d[i][0] = i;
    }
    // filling along the x axis, adjusted for pre-existing d[0][0]
    for (j = 1; j <= lenTwo; j++) {
	d[0][j] = j;
    }
    // flood fill the matrix with the edit distances, 
    // note: we'll reuse the len vars
    for (i = 1; i <= lenOne; i++) {
	for (j = 1; j <= lenTwo; j++) {
	    // if eq no edit is needed
	    eq = one[i-1] === two[j-1] ? 0 : 1;
	    d[i][j] = Math.min(
		// insertions, deletions, or nothing
		d[i-1][j]+1,
		d[i][j-1]+1,
		d[i-1][j-1] + eq);
	}
    }
    // return the last item in the matrix (return d to see the matrix)
    return d[lenOne][lenTwo];
};

// as an example, used with a node.js 'entrypoint':
// var lev = require('./levenshtein.js');
// console.log(lev.distance(process.argv[2], process.argv[3]));
//
// ~$ node entrypoint.js foshizzle fubizzle
// => 3