"npx svelte-add postcss" (or tailwindcss) fails with "The configuration file could not be found"

On latest sveltekit, getting the following errors when trying to use svelte-add to add tailwindcss or postcss.

npx svelte-add tailwindcss --jit
Need to install the following packages:
  svelte-add
Ok to proceed? (y) y
[ info ]  Applying preset svelte-add/tailwindcss.
[ error ]  The configuration file could not be found (tried in /var/folders/j4/3_1h9_mn6w5g4p438nym2vl40000gn/T/tmp-12200-fEh58kp9FH25).

This was talked about in Discord but I could not find a ticket so I’m reporting here. Hopefully this is the right place to report!

System info:

npx envinfo --system --npmPackages svelte,rollup,webpack --binaries --browsers

  System:
    OS: macOS 11.2
    CPU: (8) arm64 Apple M1
    Memory: 84.34 MB / 16.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 16.3.0 - /var/folders/j4/3_1h9_mn6w5g4p438nym2vl40000gn/T/fnm_multishells/9404_1623953947746/bin/node
    npm: 7.15.1 - /var/folders/j4/3_1h9_mn6w5g4p438nym2vl40000gn/T/fnm_multishells/9404_1623953947746/bin/npm
  Browsers:
    Brave Browser: 91.1.25.72
    Chrome: 91.0.4472.106
    Safari: 14.0.3
  npmPackages:
    svelte: ^3.34.0 => 3.38.2 

npm ls
├── @sveltejs/kit@1.0.0-next.115
├── @typescript-eslint/eslint-plugin@4.27.0
├── @typescript-eslint/parser@4.27.0
├── eslint-config-prettier@8.3.0
├── eslint-plugin-svelte3@3.2.0
├── eslint@7.28.0
├── prettier-plugin-svelte@2.3.0
├── prettier@2.2.1
├── svelte-check@2.1.0
├── svelte-preprocess@4.7.3
├── svelte@3.38.2
├── tslib@2.3.0
└── typescript@4.3.3

Repro:

npm init svelte@next myapp
cd myapp
npm i
npx svelte-add tailwindcss --jit # or just npx svelte-add postcss

[babichjacob]

It sounds like npx is using an old version of the package (maybe because of an npm audit problem). Other people have reported problems that occur for the same reason.

I do not know whether or not it works to do npx svelte-add@latest instead of just npx svelte-add, but try that and let me know if it does, please.

Otherwise, you can find the latest version of the package at https://github.com/svelte-add/svelte-add/tags and ensure npx uses it like npx svelte-add@2021.06.15.01

[babichjacob]

Those are not the right ways to write it:

npx svelte-add@latest tailwindcss and npx svelte-add@2021.06.15.01 tailwindcss.