gecko-dev/toolkit/devtools/acorn/UPGRADING.md

Assuming that acorn's dependencies have not changed, to upgrade our tree's acorn to a new version:

1. Clone the acorn repository, and check out the version you want to upgrade to:

   $ git clone https://github.com/marijnh/acorn.git
   $ cd acorn
   $ git checkout <version>
   

2. Make sure that all tests pass:

   $ npm install .
   $ npm test
   

   If there are any test failures, do not upgrade to that version of acorn!

3. Copy acorn.js to our tree:

   $ cp acorn.js /path/to/mozilla-central/toolkit/devtools/acorn/acorn.js
   

4. Copy acorn_loose.js to our tree:

   $ cp acorn_loose.js /path/to/mozilla-central/toolkit/devtools/acorn/acorn_loose.js
   

5. Copy util/walk.js to our tree:

   $ cp util/walk.js /path/to/mozilla-central/toolkit/devtools/acorn/walk.js