minimum-edit-distance.js

const input = process.argv[2];
const test = process.argv[3];
if (!input) {
    console.log('Missing input and test string');
    console.log('Usage: node minimum-edit-distance.js <input> <test>');
    process.exit(1);
}
if (!test) {
    console.log('Missing test string')
    console.log('Usage: node minimum-edit-distance.js <input> <test>');
    process.exit(1);
}

// https://gist.github.com/andrei-m/982927/0efdf215b00e5d34c90fdc354639f87ddc3bd0a5

// Compute the edit distance between the two given strings
function getEditDistance(a, b) {
    if (a.length == 0) return b.length;
    if (b.length == 0) return a.length;

    var matrix = [];

    // increment along the first column of each row
    var i;
    for (i = 0; i <= b.length; i++) {
        matrix[i] = [i];
    }

    // increment each column in the first row
    var j;
    for (j = 0; j <= a.length; j++) {
        matrix[0][j] = j;
    }

    // Fill in the rest of the matrix
    for (i = 1; i <= b.length; i++) {
        for (j = 1; j <= a.length; j++) {
            if (b.charAt(i - 1) == a.charAt(j - 1)) {
                matrix[i][j] = matrix[i - 1][j - 1];
            } else {
                matrix[i][j] = Math.min(matrix[i - 1][j - 1] + 1, // substitution
                    Math.min(matrix[i][j - 1] + 1, // insertion
                        matrix[i - 1][j] + 1)); // deletion
            }
        }
    }

    // Display matrix and inputs
    for (i = b.length; i >= 1; i--) {
        console.log(test[i - 1] + '\t' + matrix[i].filter((v, i) => i != 0).reduce((p, c, i) => { return p + '\t' + c }))
    }
    console.log('  \t' + input.split('').reduce((p, c) => { return p + '\t' + c }))

    return matrix[b.length][a.length];
};


const distance = getEditDistance(input, test);
console.log('Minimum edit is:', distance)

/*
$ node minimum-edit-distance.js gwkki hello
o       5       5       5       5       5
l       4       4       4       4       5
l       3       3       3       4       5
e       2       2       3       4       5
h       1       2       3       4       5
        g       w       k       k       i
Minimum edit is: 5
*/

https://gist.github.com/andrei-m/982927/0efdf215b00e5d34c90fdc354639f87ddc3bd0a5