test(transformer): script to amend Babel fixtures (#7122)

Add a NodeJS script which amends Babel's fixtures in place to remove transform plugins which we don't support from `options.json` files. Where options are changed from the original, the script runs Babel transform with the new options to regenerate the fixture `output.js` files.

Currently limited to transforming the fixtures for `babel-plugin-transform-class-properties` transform, but we can also enable it for other plugins if we wish in future, to get additional test coverage.

.github/workflows/ci.yml

@@ -241,6 +241,10 @@ jobs:
           save-cache: ${{ github.ref_name == 'main' }}
           tools: just
 
+      - name: Update transformer fixtures
+        if: steps.filter.outputs.src == 'true'
+        run: node tasks/transform_conformance/update_fixtures.js
+
       - name: Check Conformance
         if: steps.filter.outputs.src == 'true'
         run: |

justfile

@@ -39,6 +39,7 @@ submodules:
   just clone-submodule tasks/coverage/babel https://github.com/babel/babel.git 54a8389fa31ce4fd18b0335b05832dc1ad3cc21f
   just clone-submodule tasks/coverage/typescript https://github.com/microsoft/TypeScript.git d85767abfd83880cea17cea70f9913e9c4496dcc
   just clone-submodule tasks/prettier_conformance/prettier https://github.com/prettier/prettier.git 52829385bcc4d785e58ae2602c0b098a643523c9
+  node tasks/transform_conformance/update_fixtures.js
 
 # Install git pre-commit to format files
 install-hook: