How can I get and patch diffs in ace-editor? - diff

Question

I've heard Ace provides functionality to get and patch diffs, but I searched through Ace's docs, tried googling but couldn't find how to do that.
Do Ace provide functionality to create and patch diffs of the document being editted?
From my research, I've figured that the way to do it is using google-diff-match-patch library (https://code.google.com/p/google-diff-match-patch/). But I'd prefer using Ace's builtin mechanism if it has one.

Answer 1

We needed precisely this option for a project we're working on, so I created a lib for it: http://ace-diff.github.io/ace-diff/ - it's built on google-diff-match-patch, as 'a user' talks about, as well.
The site contains a few demos, and the code + doc is on github. Hope this helps!

Answer 2

No Ace doesn't provide a functionality to patch diffs. You need to use diff-match-patch,
e.g to diff to values apply patch to ace document use
var Range = require("ace/range").Range;
var dmplib = require("diff_match_patch");
var dmp = new dmplib.diff_match_patch();
var diff = dmp.diff_main(oldValue, newValue, true);
var offset = 0;
diff.forEach(function(chunk) {
var op = chunk[0];
var text = chunk[1];
if (op === 0) {
offset += text.length;
} else if (op === -1) {
doc.remove(Range.fromPoints(
doc.indexToPosition(offset),
doc.indexToPosition(offset + text.length)
));
} else if (op === 1) {
doc.insert(doc.indexToPosition(offset), text);
offset += text.length;
}
});

Answer 3

I needed to add capture and merging of diffs to a project today. The full, split screen library was overkill for my needs.
The following is based on a_user's code above, but written in succinct es syntax:
import dmplib from 'diff_match_patch';
export const getDiffs = (oldValue, newValue) => {
const dmp = new dmplib.diff_match_patch();
return dmp.diff_main(oldValue, newValue, true);
};
// Uses the output from above
export const mergeDiffs = diffs =>
diffs
.filter(([op]) => op > -1)
.map(([_, text]) => text)
.join('');