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🐛 BUG: Wrangler fails to compile worker when using modules that are compatible with workers (via NPM)

See original GitHub issue

What version of `Wrangler` are you using?

0.0.21

What operating system are you using?

Linux

Describe the Bug

Hi,

When creating a project via wrangler init (either with or without typescript)

You are unable to import any module from npm that is compatible with workers.

Examples tried were itty-router which is compatible with cloudflare workers and the module syntax and Cloudflare’s own @cloudflare/kv-asset-handler

Both of which provide this error when running via wrangler dev, wrangler dev --local or wrangler publish

✘ [ERROR] [plugin wrangler-module-collector] ENOENT: no such file or directory, open '/workspaces/api/src/itty-router

    src/index.ts:1:23:
      1 │ import { Router } from "itty-router";
        ╵                        ~~~~~~~~~~~~~

  This error came from the "onResolve" callback registered here:

    ../../usr/local/share/npm-global/lib/node_modules/wrangler/wrangler-dist/cli.js:138097:15:
      138097 │         build5.onResolve({
             ╵                ~~~~~~~~~

    at setup (/usr/local/share/npm-global/lib/node_modules/wrangler/wrangler-dist/cli.js:138097:16)
    at handlePlugins (/usr/local/share/npm-global/lib/node_modules/wrangler/node_modules/esbuild/lib/main.js:842:23)
    at Object.buildOrServe (/usr/local/share/npm-global/lib/node_modules/wrangler/node_modules/esbuild/lib/main.js:1136:7)
    at /usr/local/share/npm-global/lib/node_modules/wrangler/node_modules/esbuild/lib/main.js:2064:17
    at new Promise (<anonymous>)
    at Object.build (/usr/local/share/npm-global/lib/node_modules/wrangler/node_modules/esbuild/lib/main.js:2063:14)
    at Object.build (/usr/local/share/npm-global/lib/node_modules/wrangler/node_modules/esbuild/lib/main.js:1913:51)
    at bundleWorker (/usr/local/share/npm-global/lib/node_modules/wrangler/wrangler-dist/cli.js:138880:33)
    at build5 (/usr/local/share/npm-global/lib/node_modules/wrangler/wrangler-dist/cli.js:138958:75)`

It appears so though no consideration is taken for external modules or “libraries” and instead everything is assumed to be a local module accessible via ./ ?

Wrangler 1 as expected works via webpack to resolve these modules, and from what I understand Wrangler 2 is using esbuild to do the same, so I am struggling work out what is wrong that is causing even this basic code to fail. Does wrangler 2 not currently support any modules that are not ./ accessible?

This should really be supported if they aren’t there is a lot of useful frameworks or libraries that the community has created that can be used on Cloudflare workers (https://workers.cloudflare.com/works) - its a shame if wrangler 2 is going backwards in this department to not support them anymore.

Any insight into this issue would be great.

Thanks 👍