adapter-netlify missing dependency in output function

[ixxie]

Recently, I've been getting this weird error with adapter-netlify:

12:59:10 PM:   Error message
12:59:10 PM:   A Netlify Function is using "encoding" but that dependency has not been installed yet.
12:59:10 PM: ​
12:59:10 PM:   By default, dependencies inside a Netlify Function's "package.json" are not automatically installed.
  There are several ways to fix this problem:
12:59:10 PM:     - Removing your Function's "package.json" and adding the dependencies to the project's top-level "package.json" instead. This is the fastest and safest solution.
12:59:10 PM:     - Running "npm install" or "yarn" inside your Netlify Function in your build command.
12:59:10 PM:     - Adding the following plugin to your "netlify.toml":
12:59:10 PM: ​
12:59:10 PM:   [[plugins]]
12:59:10 PM:   package = "@netlify/plugin-functions-install-core"

Adding the suggested plugin doesn't seem to help...

I have not been able to reproduce the issue in a minimal repo, but my repo is public and this commit reproduces the issue.

[Leftium]

I just tried deploying the latest SvelteKit demo to Netlify without issue:

• https://sveltekit-demo-netlify-2021-05-04.netlify.app/
• https://github.com/Leftium/sveltekit-demo-netlify

So I don't think this is a SvelteKit issue, but rather an issue with your project.

---

Normally using adapter-netlify@next is recommended, but what you really want is the version that matches your SvelteKit template project. Because SvelteKit is in beta, there is no guarantee that the template project from Apr 3rd will be compatible with an adapter from Apr 30th, or even Apr 13th.

You may be able to fix the adapter issues in your project by installing a version of the adapter from around the date you initialized the project: https://www.npmjs.com/package/@sveltejs/adapter-netlify?activeTab=versions

However, what I would do is:

1. Start a new SvelteKit project with the latest template
2. Get the netlify adapter working
3. Apply your project's changes on top of this new project.

I have basically already done steps 1 and 2, so you can just clone/fork my repo:
https://github.com/Leftium/sveltekit-demo-netlify

[benmccann]

I can't run your demo. It just says supabaseUrl is required. But you should put next as the version for both SvelteKit and the adapter in your package.json and then delete your package-lock.json and run npm install again.

I'm going to close this since it's working in the default project and I can't reproduce

[Shaun-Regenbaum]

Im enountering this issue too.

[ixxie]

I tried setting SvelteKit and Adapter Netlify versions to next and reinstalling, and tried to study your fresh template repo to see if there is any difference in configuration that could cause this, but this all yielded nothing.

Can somebody explain to me what is responsible for building the functions/ folder? It seems the root of the issue relates to functions/render/index.js is requiring a dependency that isn't specified anywhere. I get no import issues when running npm run dev and I am having trouble narrowing down the source of the issue...

[agarzola]

I just encountered this as well and have a workaround.

TL;DR

Add encoding as a dependency on your project and your builds should pass:

// via npm
npm install --save encoding

// via yarn
yarn add encoding

Some background

From the build logs in Netlify:

Error message
8:11:39 AM:   A Netlify Function is using "encoding" but that dependency has not been installed yet.
8:11:39 AM: ​
8:11:39 AM:   By default, dependencies inside a Netlify Function's "package.json" are not automatically installed.
  There are several ways to fix this problem:
8:11:39 AM:     - Removing your Function's "package.json" and adding the dependencies to the project's top-level "package.json" instead. This is the fastest and safest solution.
8:11:39 AM:     - Running "npm install" or "yarn" inside your Netlify Function in your build command.
8:11:39 AM:     - Adding the following plugin to your "netlify.toml":

I tried the topmost suggestion (adding encoding as a dependency of my project) and my build passed (hence my TL;DR solution above). Then I searched for the error message online and found this support discussion wherein a commenter says that node-fetch is the culprit, which led me down a rabbit hole…

Check if your project has a dependency (nested or otherwise) on node-fetch:

// via npm
npm ls node-fetch

// via yarn
yarn why node-fetch

In my project, I’m using @prismicio/client, which has a dependency on node-fetch. Here’s what yarn why node-fetch yields:

=> Found "node-fetch@2.6.1"
info Reasons this module exists
   - "@prismicio#client#cross-fetch" depends on it
   - Hoisted from "@prismicio#client#cross-fetch#node-fetch"

node-fetch attempts to load encoding (and catches the error if it cannot be found), but encoding is not listed as its dependency. I have zero experience with any of the tech involved in this (Svelte, SvelteKit, Vite, and Netlify Functions are all new to me! 😄), but I think that when the Netlify function is generated by the Netlify adapter, the encoding package is identified as a requirement and the generated file ends up with a hard dependency on it. Since the package is not in the list of dependencies for node-fetch, it is never installed.

This definitely is not technically an issue with SvelteKit or its Netlify adapter. It’s just the result of the way that functions are packaged and a failure of whatever shrink-wrapping function is being used for that to identify when a require() statement is composed in such a way as to make the dependency optional.

I hope this helps others running into this issue!

[ixxie]

Thank you @agarzola, this resolves the issue for me.

I wonder if an issue should be opened in the node-fetch repo?

I would be happy to do it, but you seem to have a better grasp of the topic.

[agarzola]

@ixxie I’m glad that helped!

I wonder if an issue should be opened in the node-fetch repo?

Feel free to give it a shot, but this comment indicates that they don’t intend to add encoding as a dependency. I get where they’re coming from: node-fetch technically does not depend on the package, it only checks if it’s available and, if it isn’t handles the error and carries on without it. node-fetch isn’t really the one throwing the error in your project or mine. The error is a byproduct of the way packages are bundled.

The bundler encounters node-fetch’s try { convert = require('encoding').convert; } catch (e) {} statement and (understandably) presumes encoding is a hard requirement, so it includes a require statement in the bundle. The bundler has no awareness of the “optionality” (so to speak) of the require() statement (since it’s wrapped in a try/catch).

Is it really node-fetch’s responsibility to be aware of how bundlers evaluate packages? 🤷 I think arguments could be made either way. In any case, it appears that the upcoming v3 of node-fetch (still in beta) does away with this entirely, so the solution above is temporary.

[ixxie]

Right, I see your point. Well, I'll leave it to better minds to think about the issues of bundling and dependencies...

[samyoungnyc]

I'm experiencing the exact same problem but my error code is:

A Netlify Function is using "exports" but that dependency has not been installed yet.

Tried to install 'exports' but got the following error:

npm ERR! notsup Unsupported engine for super@0.1.0: wanted: {"node":">= 0.6.0 < 0.7.0"} (current: {"node":"14.17.0","npm":"6.14.13"})

FWIW if anyone is interested I'd greatly appreciate help with this, I'm totally flummoxed.