Flag to start next dev without cache

[gaearon]

Describe the feature you'd like to request

I want to be able to make edits in node_modules and see the result without restarting the server. This is indispensable for debugging libraries, including Next.js itself.

Describe the solution you'd like

yarn dev --no-cache

Build cache gets disabled. If I edit node_modules, I don't need to restart the server.

Describe alternatives you've considered

What I do now:

rm -rf .next/cache
yarn dev

(make an edit)

rm -rf .next/cache
yarn dev

(make an edit)

rm -rf .next/cache
yarn dev

but this is not fun.

[migueloller]

To add some extra info to the discussion, this also makes it very hard to work with separate repos when using npm link or yarn link since Next.js sees those as being in node_modules and doesn't reload when changes are made.

[Robert-Schirmer]

I've been able to get hot refresh on changes to certain node_module with this next.config.js.

By default all files in node_modules webpack assumes will not be modified. We need to update the managedPaths property of the webpack snapshot config to exclude whatever modules you want webpack to watch for changes in.
https://webpack.js.org/configuration/other-options/#managedpaths

let config = {
  reactStrictMode: true,
  swcMinify: true,
  eslint: {
    dirs: ['pages', 'src', '__tests__', 'cypress'],
  },
  webpack: (config) => {
    config.snapshot = {
      ...(config.snapshot ?? {}),
      // Add all node_modules but @next module to managedPaths
      // Allows for hot refresh of changes to @next module
      managedPaths: [/^(.+?[\\/]node_modules[\\/])(?!@next)/],
    };
    return config;
  },
};

if (process.env.ANALYZE === 'true') {
  const withBundleAnalyzer = require('@next/bundle-analyzer')({
    enabled: true,
  });
  config = withBundleAnalyzer(config);
}

module.exports = config;

[hirbod]

@Robert-Schirmer I want to give you the biggest hug in this world right now. You can't believe how annoyed I was with our bit managed modules. I owe you the biggest thank you!!!!

[ehxxn]

how would you do that with a monorepo

[alexandre-tobia]

@hirbod Hi, i'm working with bit too but i can't make the solution provided by @Robert-Schirme work. Could you share your config ? It would be awesome ! thanks in advance

[AdarshKonchady]

The above solution didn't work for me either. Wondering if it was working on a previous NextJs version.

[alexandre-tobia]

I've made it working with that next.config:

module.exports = {
  webpack: (config, { buildId, dev, isServer, defaultLoaders, nextRuntime, webpack }
  ) => {

    if(dev) {
      config.watchOptions = {
        followSymlinks: true,
      }

      config.snapshot.managedPaths = [];
      
    }

    return config;
  },
}

Not ideal in perf, but it works.

[paranat]

Just want to say that I'd really love to see this. Next engages in some aggressive caching of components, which can cause a lot of confusion during development. I would really like to see a solution for opting out of said caching during development without having to add code that will mess up the caching on production.

It can be an especially bad issue when switching between branches of a codebase.

[rusakovic]

Interesting that @gaearon himself wrote about this issue =)
Still in progress - it's strange from @vercel side

[ApplePieGiraffe]

Any update on this? This is making locally developing a package to be consumed by a Next app difficult for us as you have to delete .next/cache and restart the server to see any changes you make to the package in the Next app

[nbkhope]

Having the same problem. Wish there was an ideal solution for this, not necessarily what this issue is asking for. Maybe related to #57811

[elyselibetti]

Any updates on this? Caching on development feels like the polar opposite of what "development" is.