npm package for https://code.google.com/p/google-diff-match-patch/
npm install diff-match-patch
https://code.google.com/p/google-diff-match-patch/wiki/API
var DiffMatchPatch = require('diff-match-patch');
var dmp = new DiffMatchPatch();
//use the methods that dmp has
//see: https://code.google.com/p/google-diff-match-patch/wiki/API
//You can also use the following properties:
DiffMatchPatch.DIFF_DELETE = -1;
DiffMatchPatch.DIFF_INSERT = 1;
DiffMatchPatch.DIFF_EQUAL = 0;