Fix text diffing by replacing 'diff-match-patch' with '@dmsnell/diff-match-patch'

[atsjo]

'diff-match-patch' have issues with surrogate pairs when diffing, you can test it in the live demo by changing:
left

...
"summary": "South America😀👍...
...

right

...
"summary": "South America👍...
...

Then the diff below disappears and you can see this error in console:

URIError: URI malformed
    at encodeURI (<anonymous>)
    at diff_match_patch.patch_obj.toString (demo.js:1476:30)
    at Array.join (<anonymous>)
    at diff_match_patch.patch_toText (demo.js:1377:21)
    at diff (demo.js:2457:28)
    at textsDiffFilter (demo.js:2490:24)
    at Pipe.process (demo.js:1570:9)
    at Processor.process (demo.js:1537:18)
    at DiffPatcher.diff (demo.js:2560:29)
    at compare2 (demo.js:3470:30)

In my own use of jsondiffpatch I have replaced diff-match-patch like this:

import type { Options } from 'jsondiffpatch';
import { diff_match_patch } from '@dmsnell/diff-match-patch';
/** replacing diff-match-patch with version from dmsnell which fixes surrogate pair problems  */
export const CustomDMP = diff_match_patch as unknown as NonNullable<Options['textDiff']>['diffMatchPatch'];

and then importing CustomDMP into jsondiffpatch via options...

• see Project abandoned / dead / maintained? google/diff-match-patch#143 for more context
• the import used by jsondiffpatch is also not maintained https://github.com/JackuB/diff-match-patch

As a bonus @dmsnell/diff-match-patch is also exported as esm...

[atsjo]

And many thanks for a powerful library with an api that actually allowed me to replace this dependency, and also create my own custom formatter with support for text diff patches👍

[benjamine]

hi @atsjo thank you!
thanks for sharing and finding the alternative, I'll take a look, we've always debated removing the dependency completely (and make it always an opt-in) but now it's delicate because of backwards compat concerns.

is @dmsnell fork published to npm?
would be ideal if we can merge fixed back to @JackuB 's or agree on a fork to maintain.

[atsjo]

yes it's on npm, so this is a very simple fix: "@dmsnell/diff-match-patch": "^1.1.0"
I use it, and it works perfect, beside from the hacky import... the repo is at https://github.com/dmsnell/diff-match-patch. This is the only maintained repo with an actual fix I could find, and this is also where the people fixing the issue agreed to maintain it: dmsnell/diff-match-patch#8

[atsjo]

Thanx for the fix @benjamine, and the other fixes as well, I can now also enable moves again:-) Regarding my custom formatter implementation I have opened another issue with an associated PR for a easy way to extend JSONFormatter...