1908327 - Migrate from Babel to lezer in debugger frontend usages

Status: ASSIGNED

(DevTools :: Debugger, enhancement)

Description

[Alexandre Poirot [:ochameau]]

Babel parser (parser-worker.js) is by far the main performance culprit of the Debugger.

We do use the parser for various debugger frontend features, highlighted in the following document:
https://docs.google.com/document/d/12xq6Q5qDEuNDtKwSm9LwKSUA4k_zT-r96-3TWIimoqA/edit#heading=h.ldmzcj1wna5e

Thanks to the migration to CodeMirror 6 (bug 1773246), we will be able to use its new parser lezer.
This parser supports parsing only chunks of code and will allow us to only parse the current viewport.
Babel only supports parsing the whole file, which is the main reason why this particular part of the debugger is slow.

Comment 1

[Hubert Boma Manilla (:bomsy)]

Attachment: WIP: Bug 1908327 - [devtools] Migrate getting in scope locations from CM6 parser instead of the parser worker