`npm ls -a` reports unmet dependency errors on WASM package when installing `@tailwindcss/postcss`

[foobar-star]

Possible Bug Report

What version of Tailwind CSS are you using? @tailwindcss/postcss@4.1.14 and tailwindcss@4.1.14

What build tool (or framework if it abstracts the build tool) are you using? npx create-next-app@latest or node.js

What version of Node.js are you using? v24.10.0 and v22.10.0

What browser are you using? N/A

What operating system are you using? Linux

Reproduction URL

Installing Tailwind CSS v4 in next.js projects or just plain node.js (specifically @tailwindcss/postcss@4.1.14) introduces either extraneous WebAssembly dependencies such as @emnapi/runtime(if using npm 11 and node version 22) or ESLProblems If using npm 11+ and node 24. In the former issue(node v 22) extraneous dependencies cannot be removed by standard methods (npm uninstall, npm prune, --ignore-scripts, etc.) and persist after installation and get reinstalled by post install scripts from napi-postinstall causing confusion and potentially interfering with clean environments or minimal builds.

Keep in mind these steps have only been identified when the sharp package is present either as a direct or as a transitive dependency. Sharp is a transitive dependency by default in all next.js projects.

You can reproduce these issues here: https://codesandbox.io/p/sandbox/github/vercel/next.js/tree/canary/examples/reproduction-template?file=%2F.gitignore

This issue originally was brought up here: vercel/next.js#84450 and lovell/sharp#4464 was thought to be caused by create-next-app, and the sharp packages Emscripten detection which uses similar WebAssembly binaries as tailwind and rebuilds them post-install lovell/sharp#4442.

The two specific packages thought to explain the issue now are eslint-config-next@15.5.4 and @tailwindcss/postcss@4.1.14 by the way of tailwindcss/oxide-wasm32-wasi, unrs-resolver (optional dependency of eslint-config-next.js). See full explanation here: vercel/next.js#84450 (comment)

Here are the exact steps to reproduce the issues using node version 22.10.0

To Reproduce

$ node -v
v22.10.0
$ npm -v
11.6.1

$ npx create-next-app@latest my-app -ts -tw -eslint
if flags are not working please select typescript, tailwind, and eslint


$ npm ls
my-app@0.1.0 /project/workspace/my-app
├── @emnapi/core@1.5.0 extraneous
├── @emnapi/runtime@1.5.0 extraneous
├── @emnapi/wasi-threads@1.1.0 extraneous
├── @eslint/eslintrc@3.3.1
├── @napi-rs/wasm-runtime@0.2.12 extraneous
├── @tailwindcss/postcss@4.1.14
├── @tybys/wasm-util@0.10.1 extraneous
├── @types/node@20.19.21
├── @types/react-dom@19.2.2
├── @types/react@19.2.2
├── eslint-config-next@15.5.5
├── eslint@9.37.0
├── next@15.5.5
├── react-dom@19.1.0
├── react@19.1.0
├── tailwindcss@4.1.14
└── typescript@5.9.3

Traditional cleanup commands have no effect so running npm uninstall emnapi/runtime@1.5.0 or other cleanup commands (npm prune, reinstalling, clearing caches, ignore scripts) does not remove it or Post Install scripts from optional dependencies make these persist. vercel/next.js#84450 (comment)

OR with node 24+ and NPM 11+ and installing @tailwindcss/postcss as per lovell lovell/sharp#4464 (comment)

$ node -v
v24.10.0

$ npm -v
11.6.1

$ cat package.json 
{
  "dependencies": {
    "@tailwindcss/postcss": "^4.1.14",
    "sharp": "^0.34.4"
  }
}

$ npm install

added 76 packages, and audited 77 packages in 2s

38 packages are looking for funding
  run `npm fund` for details

found 0 vulnerabilities

$ npm ls
├── @tailwindcss/postcss@4.1.14
└── sharp@0.34.4

$ ls -w1 node_modules/@img
colour
sharp-libvips-linux-x64
sharp-linux-x64

$ npm ls --all
├─┬ @tailwindcss/postcss@4.1.14
│ ├── @alloc/quick-lru@5.2.0
│ ├─┬ @tailwindcss/node@4.1.14
│ │ ├─┬ @jridgewell/remapping@2.3.5
│ │ │ ├─┬ @jridgewell/gen-mapping@0.3.13
│ │ │ │ ├── @jridgewell/sourcemap-codec@1.5.5 deduped
│ │ │ │ └── @jridgewell/trace-mapping@0.3.31 deduped
│ │ │ └─┬ @jridgewell/trace-mapping@0.3.31
│ │ │   ├── @jridgewell/resolve-uri@3.1.2
│ │ │   └── @jridgewell/sourcemap-codec@1.5.5 deduped
│ │ ├─┬ enhanced-resolve@5.18.3
│ │ │ ├── graceful-fs@4.2.11
│ │ │ └── tapable@2.3.0
│ │ ├── jiti@2.6.1
│ │ ├─┬ lightningcss@1.30.1
│ │ │ ├── detect-libc@2.1.2 deduped
│ │ │ ├── lightningcss-darwin-arm64@1.30.1
│ │ │ ├── lightningcss-darwin-x64@1.30.1
│ │ │ ├── lightningcss-freebsd-x64@1.30.1
│ │ │ ├── lightningcss-linux-arm-gnueabihf@1.30.1
│ │ │ ├── lightningcss-linux-arm64-gnu@1.30.1
│ │ │ ├── lightningcss-linux-arm64-musl@1.30.1
│ │ │ ├── lightningcss-linux-x64-gnu@1.30.1
│ │ │ ├── lightningcss-linux-x64-musl@1.30.1
│ │ │ ├── lightningcss-win32-arm64-msvc@1.30.1
│ │ │ └── lightningcss-win32-x64-msvc@1.30.1
│ │ ├─┬ magic-string@0.30.19
│ │ │ └── @jridgewell/sourcemap-codec@1.5.5
│ │ ├── source-map-js@1.2.1
│ │ └── tailwindcss@4.1.14 deduped
│ ├─┬ @tailwindcss/oxide@4.1.14
│ │ ├── @tailwindcss/oxide-android-arm64@4.1.14
│ │ ├── @tailwindcss/oxide-darwin-arm64@4.1.14
│ │ ├── @tailwindcss/oxide-darwin-x64@4.1.14
│ │ ├── @tailwindcss/oxide-freebsd-x64@4.1.14
│ │ ├── @tailwindcss/oxide-linux-arm-gnueabihf@4.1.14
│ │ ├── @tailwindcss/oxide-linux-arm64-gnu@4.1.14
│ │ ├── @tailwindcss/oxide-linux-arm64-musl@4.1.14
│ │ ├── @tailwindcss/oxide-linux-x64-gnu@4.1.14
│ │ ├── @tailwindcss/oxide-linux-x64-musl@4.1.14
│ │ ├─┬ @tailwindcss/oxide-wasm32-wasi@4.1.14
│ │ │ ├── UNMET DEPENDENCY @emnapi/core@^1.5.0
│ │ │ ├── @emnapi/runtime@1.5.0 deduped
│ │ │ ├── UNMET DEPENDENCY @emnapi/wasi-threads@^1.1.0
│ │ │ ├── UNMET DEPENDENCY @napi-rs/wasm-runtime@^1.0.5
│ │ │ ├── UNMET DEPENDENCY @tybys/wasm-util@^0.10.1
│ │ │ └── tslib@2.8.1
│ │ ├── @tailwindcss/oxide-win32-arm64-msvc@4.1.14
│ │ ├── @tailwindcss/oxide-win32-x64-msvc@4.1.14
│ │ ├── detect-libc@2.1.2 deduped
│ │ └─┬ tar@7.5.1
│ │   ├─┬ @isaacs/fs-minipass@4.0.1
│ │   │ └── minipass@7.1.2 deduped
│ │   ├── chownr@3.0.0
│ │   ├── minipass@7.1.2
│ │   ├─┬ minizlib@3.1.0
│ │   │ └── minipass@7.1.2 deduped
│ │   └── yallist@5.0.0
│ ├─┬ postcss@8.5.6
│ │ ├── nanoid@3.3.11
│ │ ├── picocolors@1.1.1
│ │ └── source-map-js@1.2.1 deduped
│ └── tailwindcss@4.1.14
└─┬ sharp@0.34.4
  ├── @img/colour@1.0.0
  ├─┬ @img/sharp-darwin-arm64@0.34.4
  │ └── @img/sharp-libvips-darwin-arm64@1.2.3 deduped
  ├─┬ @img/sharp-darwin-x64@0.34.4
  │ └── @img/sharp-libvips-darwin-x64@1.2.3 deduped
  ├── @img/sharp-libvips-darwin-arm64@1.2.3
  ├── @img/sharp-libvips-darwin-x64@1.2.3
  ├── @img/sharp-libvips-linux-arm@1.2.3
  ├── @img/sharp-libvips-linux-arm64@1.2.3
  ├── @img/sharp-libvips-linux-ppc64@1.2.3
  ├── @img/sharp-libvips-linux-s390x@1.2.3
  ├── @img/sharp-libvips-linux-x64@1.2.3
  ├── @img/sharp-libvips-linuxmusl-arm64@1.2.3
  ├── @img/sharp-libvips-linuxmusl-x64@1.2.3
  ├─┬ @img/sharp-linux-arm@0.34.4
  │ └── @img/sharp-libvips-linux-arm@1.2.3 deduped
  ├─┬ @img/sharp-linux-arm64@0.34.4
  │ └── @img/sharp-libvips-linux-arm64@1.2.3 deduped
  ├─┬ @img/sharp-linux-ppc64@0.34.4
  │ └── @img/sharp-libvips-linux-ppc64@1.2.3 deduped
  ├─┬ @img/sharp-linux-s390x@0.34.4
  │ └── @img/sharp-libvips-linux-s390x@1.2.3 deduped
  ├─┬ @img/sharp-linux-x64@0.34.4
  │ └── @img/sharp-libvips-linux-x64@1.2.3 deduped
  ├─┬ @img/sharp-linuxmusl-arm64@0.34.4
  │ └── @img/sharp-libvips-linuxmusl-arm64@1.2.3 deduped
  ├─┬ @img/sharp-linuxmusl-x64@0.34.4
  │ └── @img/sharp-libvips-linuxmusl-x64@1.2.3 deduped
  ├─┬ @img/sharp-wasm32@0.34.4
  │ └─┬ @emnapi/runtime@1.5.0
  │   └── tslib@2.8.1 deduped
  ├── @img/sharp-win32-arm64@0.34.4
  ├── @img/sharp-win32-ia32@0.34.4
  ├── @img/sharp-win32-x64@0.34.4
  ├── detect-libc@2.1.2
  └── semver@7.7.3

npm error code ELSPROBLEMS
npm error missing: @emnapi/core@^1.5.0, required by @tailwindcss/oxide-wasm32-wasi@4.1.14
npm error missing: @emnapi/wasi-threads@^1.1.0, required by @tailwindcss/oxide-wasm32-wasi@4.1.14
npm error missing: @napi-rs/wasm-runtime@^1.0.5, required by @tailwindcss/oxide-wasm32-wasi@4.1.14
npm error missing: @tybys/wasm-util@^0.10.1, required by @tailwindcss/oxide-wasm32-wasi@4.1.14

additional steps taken to identify/resolve the underlying issue shared below

$ node -v
v24.10.0
$ npm -v
11.6.1
$ npx create-next-app@latest my-app -ts -tw -eslint (if these options do not work please just select typescript, tailwind, and eslint from the prompt)

$ npm ls -all | grep -i invalid
│ │ │ ├─┬ @napi-rs/wasm-runtime@0.2.12 invalid: "^1.0.5" from node_modules/@tailwindcss/oxide-wasm32-wasi
│ │   │ └── @napi-rs/wasm-runtime@0.2.12 deduped invalid: "^1.0.5" from node_modules/@tailwindcss/oxide-wasm32-wasi
npm error code ELSPROBLEMS
npm error invalid: @napi-rs/wasm-runtime@0.2.12 /project/workspace/my-app/node_modules/@napi-rs/wasm-runtime


$ rm -rf node_modules/sharp   
$ rm package-lock.json     
$ npm cache clean --force

$ npm install


$ npm ls -all | grep -i invalid
$

and also here for node version 22 LTS

$ node -v
v22.10.0
$ npm -v
11.6.1

$ npx create-next-app@latest my-app -ts -tw -eslint
if flags are not working please select typescript, tailwind, and eslint


$ npm ls
my-app@0.1.0 /project/workspace/my-app
├── @emnapi/core@1.5.0 extraneous
├── @emnapi/runtime@1.5.0 extraneous
├── @emnapi/wasi-threads@1.1.0 extraneous
├── @eslint/eslintrc@3.3.1
├── @napi-rs/wasm-runtime@0.2.12 extraneous
├── @tailwindcss/postcss@4.1.14
├── @tybys/wasm-util@0.10.1 extraneous
├── @types/node@20.19.21
├── @types/react-dom@19.2.2
├── @types/react@19.2.2
├── eslint-config-next@15.5.5
├── eslint@9.37.0
├── next@15.5.5
├── react-dom@19.1.0
├── react@19.1.0
├── tailwindcss@4.1.14
└── typescript@5.9.3


$ npm ls -all | grep -i invalid
$ 
$ rm -rf node_modules/sharp 
$ rm package-lock.json
$ npm cache clean --force
$ npm install sharp --no-optional
$ npm ls            
my-app@0.1.0 /project/workspace/my-app
├── @eslint/eslintrc@3.3.1
├── @tailwindcss/postcss@4.1.14
├── @types/node@20.19.21
├── @types/react-dom@19.2.2
├── @types/react@19.2.2
├── eslint-config-next@15.5.5
├── eslint@9.37.0
├── next@15.5.5
├── react-dom@19.1.0
├── react@19.1.0
├── sharp@0.34.4
├── tailwindcss@4.1.14
└── typescript@5.9.3

$ npm ls -all | grep -i invalid
$

Sometimes removing the optional deps of Sharp resolved the issues entirely (as did it with tailwind or eslint). However, the sharp maintainer mentioned this is probably a question better suited for the @tailwindcss/oxide-wasm32-wasi maintainer and if not may be a bug with NPM.

Thank you!

[thecrypticace]

Installing @tailwindcss/postcss does not install the WASM dependencies. They show up in npm ls -a but they're not actually installed.

If you check the files in your node_modules folder you can see this:

I'm not sure why npm ls -a is reporting unmet dependency errors. Maybe we need to also mark them as peers? I thought Optional dependencies should be enough 🤔

[thecrypticace]

I think there's definitely an NPM bug in here somewhere but maybe something with our package too?

This errors:

npm init -y
npm install @tailwindcss/postcss
npm ls -a

This does not and produces zero unmet dependency errors:

npm init -y
npm install sharp
npm ls -a

This produces unmet dependency warnings (but only sometimes??):

npm init -y
npm install sharp
rm -rf package-lock.json
npm install
npm ls -a

Likewise, with our package, this produces unmet dependency warnings (but only sometimes?? — other times it errors):

npm init -y
npm install @tailwindcss/postcss
rm -rf package-lock.json
npm install
npm ls -a

I can also occasionally reproduce this when deleting node_modules but i think less often?

If the previous step for sharp produced dependency warnings then you install @tailwindcss/postcss it also produces warnings instead of errors after installing it.

e.g. sometimes this produces a warning and sometimes an error:

npm init -y
npm install sharp
rm -rf package-lock.json
npm install
npm ls -a
npm install @tailwindcss/postcss
npm ls -a

[Arun-kushwaha007]

Hi all,

I’ve been debugging this issue myself and wanted to share my findings and a clear reproduction so others can reproduce and investigate.

---

Environment

• Tailwind CSS version: tailwindcss@4.1.14 and @tailwindcss/postcss@4.1.14
• Node.js version: v22.10.0 and v24.10.0
• NPM version: 11.6.1
• OS: Linux
• Build tool / Framework: plain Node.js and create-next-app@latest

---

Description

When I install Tailwind CSS v4 in Next.js projects or plain Node.js (specifically @tailwindcss/postcss@4.1.14), I see either:

1. Extraneous WebAssembly dependencies like @emnapi/runtime (with Node v22 & npm 11)
2. ELSPROBLEMS errors (with Node v24 & npm 11+)

I believe the problem is linked to optional WASM dependencies (@tailwindcss/oxide-wasm32-wasi) and their interaction with Sharp as a transitive dependency.

I found these dependencies often cannot be removed by standard cleanup commands (npm uninstall, npm prune, --ignore-scripts, clearing cache) because post-install scripts reinstall them, which makes maintaining a clean environment difficult.

---

Reproduction Steps

Node v22.10.0 & npm 11.6.1

$ node -v
v22.10.0
$ npm -v
11.6.1
$ npx create-next-app@latest my-app -ts -tw -eslint
# (select TypeScript, Tailwind, ESLint if flags don’t work)

$ npm ls
my-app@0.1.0
├── @emnapi/core@1.5.0 extraneous
├── @emnapi/runtime@1.5.0 extraneous
├── @emnapi/wasi-threads@1.1.0 extraneous
├── @napi-rs/wasm-runtime@0.2.12 extraneous
├── @tybys/wasm-util@0.10.1 extraneous
├── @tailwindcss/postcss@4.1.14
├── tailwindcss@4.1.14
...

Running npm ls -all | grep -i invalid produced nothing at first for me, but I observed the optional dependencies persisted in node_modules and were reinstalled after any postinstall script ran.

Node v24.10.0 & npm 11.6.1

$ node -v
v24.10.0
$ npm -v
11.6.1
$ npm init -y
$ npm install @tailwindcss/postcss@4.1.14 sharp
$ npm ls -a | grep -i invalid
npm error code ELSPROBLEMS
npm error missing: @emnapi/core@^1.5.0
npm error missing: @emnapi/wasi-threads@^1.1.0
npm error missing: @napi-rs/wasm-runtime@^1.0.5
npm error missing: @tybys/wasm-util@^0.10.1

Even after I removed node_modules/sharp, deleted the lockfile, cleared the cache, and reinstalled packages, these dependencies either remained extraneous or produced ELSPROBLEMS warnings in subsequent installs.

---

Observations

• npm ls -a consistently lists @tailwindcss/oxide-wasm32-wasi dependencies as missing, but the folder often never exists on disk.
• Installing with --no-optional sometimes prevents the optional WASM packages from being present.
• The behavior is inconsistent and seems influenced by npm’s handling of optional dependencies, WASM binaries, and postinstall scripts.

Sharp maintainers noted this might be more relevant to the @tailwindcss/oxide-wasm32-wasi package or NPM itself.

Conclusion

From my testing, this appears to be an npm edge case or bug involving optional WASM dependencies and postinstall behavior:

• Optional dependencies in @tailwindcss/oxide-wasm32-wasi are reported as missing by npm ls -a but are not actually installed.
• Postinstall scripts in Sharp or other packages can reinstall these binaries, causing persistent extraneous dependencies.
• Standard cleanup commands (rm -rf node_modules, npm prune, clearing cache) are often insufficient.

References

• Original Next.js issue: vercel/next.js#84450
• Sharp WASM discussion: lovell/sharp#4464
• Sharp postinstall explanation: lovell/sharp#4442

[Arun-kushwaha007]

Here's what worked for me:

1. First, I cleaned up everything:

# Remove existing dependencies
rm -rf node_modules package-lock.json

# Clean npm cache completely
npm cache clean --force

2. Then installed Tailwind with these specific flags:

npm install @tailwindcss/postcss@4.1.15 --legacy-peer-deps --force

3. Verified the fix:

npm ls -a | grep -i invalid

The Results

After following these steps:

• No more extraneous WASM binaries
• ELSPROBLEMS errors disappeared
• Clean and stable environment
• No manual cleanup needed for packages like @emnapi, @napi-rs, or @tybys

This solution worked consistently for me on both:

• Node v22.10.0 + npm 11.6.1
• Node v24.10.0 + npm 11.6.1

Why This Works

The key was using both --legacy-peer-deps and --force flags together. This seems to prevent the problematic optional WASM dependencies from being installed while maintaining the core functionality.

[sebcomeau]

Build fails during npm prune --production with the following error:

ENOENT: no such file or directory, lstat '/home/node/node_modules/@tailwindcss/oxide-wasm32-wasi'

This happens because the package-lock.json was generated on a Windows machine, but the Docker build runs on Linux. Tailwind’s @tailwindcss/oxide-* dependencies are platform-specific, and the lockfile references the Windows variants. When npm prunes dependencies on Linux, it can’t find the corresponding binaries, leading to the missing file error.

[sebcomeau]

Can't do a clean install on Windows because we've recreated the package lockfile on Linux.

Windows 11
Node v24.11.0
NPM v11.6.2

$ npm ci
npm error code EUSAGE
npm error
npm error `npm ci` can only install packages when your package.json and package-lock.json or npm-shrinkwrap.json are in sync. Please update your lock file with `npm install` before continuing.
npm error
npm error Missing: @tailwindcss/oxide-wasm32-wasi@4.1.16 from lock file
npm error
npm error Clean install a project
npm error
npm error Usage:
npm error npm ci
npm error
npm error Options:
npm error [--install-strategy <hoisted|nested|shallow|linked>] [--legacy-bundling]
npm error [--global-style] [--omit <dev|optional|peer> [--omit <dev|optional|peer> ...]]
npm error [--include <prod|dev|optional|peer> [--include <prod|dev|optional|peer> ...]]
npm error [--strict-peer-deps] [--foreground-scripts] [--ignore-scripts] [--no-audit]
npm error [--no-bin-links] [--no-fund] [--dry-run]
npm error [-w|--workspace <workspace-name> [-w|--workspace <workspace-name> ...]]
npm error [--workspaces] [--include-workspace-root] [--install-links]
npm error
npm error aliases: clean-install, ic, install-clean, isntall-clean
npm error
npm error Run "npm help ci" for more info