RFC: Add support for 'export default { fetch() }' in Pages Functions

[GregBrimble]

This PR makes it possible to use a regular ol' export default { fetch() } within Pages Functions.

Any onRequest(Get|Head|Post|etc) take precedence, and if an onRequest is also included, the export default { fetch() } is not invoked.

I welcome feedback on the idea, and on the priority described above.

The only feature that's missing is passThroughOnException(), which we don't have in Pages Functions normally anyway.

---

To Do

• [ ] Log a warning on conflict between export const onRequest and export default { fetch() }

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: c0a768e8bc28f8352b4f572a375e332da72838f6

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
wrangler	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions[bot]]

A wrangler prerelease is available for testing. You can install this latest build in your project with:

npm install --save-dev https://prerelease-registry.developers.workers.dev/runs/2971109719/npm-package-wrangler-1740

You can reference the automatically updated head of this PR with:

npm install --save-dev https://prerelease-registry.developers.workers.dev/prs/1740/npm-package-wrangler-1740

Or you can use npx with this latest build directly:

npx https://prerelease-registry.developers.workers.dev/runs/2971109719/npm-package-wrangler-1740 dev path/to/script.js

[codecov[bot]]

Codecov Report

Merging #1740 (c0a768e) into main (2b847a2) will decrease coverage by 0.04%. The diff coverage is 50.00%.

@@            Coverage Diff             @@
##             main    #1740      +/-   ##
==========================================
- Coverage   80.24%   80.19%   -0.05%     
==========================================
  Files          92       93       +1     
  Lines        6190     6226      +36     
  Branches     1597     1605       +8     
==========================================
+ Hits         4967     4993      +26     
- Misses       1223     1233      +10     

Impacted Files	Coverage Δ
packages/wrangler/src/pages/functions/routes.ts	8.33% <0.00%> (-0.37%)	:arrow_down:
...s/wrangler/src/pages/functions/filepath-routing.ts	87.27% <47.05%> (-7.36%)	:arrow_down:
...ckages/wrangler/src/pages/functions/buildPlugin.ts	15.00% <100.00%> (+2.17%)	:arrow_up:
...ckages/wrangler/src/pages/functions/buildWorker.ts	13.72% <100.00%> (+1.72%)	:arrow_up:
packages/wrangler/src/pages/functions/esbuild.ts	100.00% <100.00%> (ø)
packages/wrangler/src/dev.tsx	81.28% <0.00%> (+1.53%)	:arrow_up:
...ackages/wrangler/src/__tests__/helpers/mock-bin.ts	100.00% <0.00%> (+5.26%)	:arrow_up:

[Cherry]

How would this work with the new middleware stuff for Workers? https://github.com/cloudflare/wrangler2/pull/1735

Would that also be compatible here if/when it was exposed for user-facing stuff?

[cameron-robey]

How would this work with the new middleware stuff for Workers? #1735

Would that also be compatible here if/when it was exposed for user-facing stuff?

The middleware works by being bundled in with wrangler (i.e. a non-bundled worker pushed up to the edge wouldn't register any of the middleware exported), so functions might have to implement it separately if they don't get bundled in the same way - would be nice to have the same interface and compatibility of middleware though

[petebacondarwin]

Closing this as we are encouraging people to create a _workers.js Worker in cases where Pages users want more control.