`SyntaxError: Unexpected identifier 'assert'` on build

[hejops]

Node.js removed support for import assertions a while ago, so rollup.config.mjs is technically invalid now. I thought I could work around this by simply replacing assert with with, but rollup still thinks there is an assert somewhere.

I'm on node 23.7.0. Presumably versions >= 22 will be affected.

To reproduce:

cd /tmp
rm -rf discojs
git clone https://github.com/aknorw/discojs
cd discojs
yarn install

yarn rollup --version

yarn build || :
sed -i 's/assert/with/' rollup.config.mjs
yarn build || :

Cloning into 'discojs'...
remote: Enumerating objects: 1150, done.
remote: Counting objects: 100% (217/217), done.
remote: Compressing objects: 100% (116/116), done.
remote: Total 1150 (delta 128), reused 101 (delta 101), pack-reused 933 (from 1)
Receiving objects: 100% (1150/1150), 1.18 MiB | 2.33 MiB/s, done.
Resolving deltas: 100% (762/762), done.
yarn install v1.22.22
[1/5] Validating package.json...
[2/5] Resolving packages...
[3/5] Fetching packages...
warning rollup-plugin-ts@3.4.5: The engine "pnpm" appears to be invalid.
warning browserslist-generator@2.1.0: The engine "pnpm" appears to be invalid.
[4/5] Linking dependencies...
warning " > typedoc@0.19.2" has incorrect peer dependency "typescript@3.9.x || 4.0.x".
[5/5] Building fresh packages...
$ husky
Done in 1.20s.
yarn run v1.22.22
$ /tmp/discojs/node_modules/.bin/rollup --version
rollup v4.21.0
Done in 0.16s.
yarn run v1.22.22
$ rimraf dist && rollup -c
[!] SyntaxError: Unexpected identifier 'assert'
    at compileSourceTextModule (node:internal/modules/esm/utils:338:16)
    at ModuleLoader.moduleStrategy (node:internal/modules/esm/translators:106:18)
    at ModuleLoader.#translate (node:internal/modules/esm/loader:473:12)
    at ModuleLoader.loadAndTranslate (node:internal/modules/esm/loader:520:27)
    at ModuleJob._link (node:internal/modules/esm/module_job:115:19)


error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
yarn run v1.22.22
$ rimraf dist && rollup -c
[!] SyntaxError: Unexpected identifier 'assert'
    at compileSourceTextModule (node:internal/modules/esm/utils:338:16)
    at ModuleLoader.moduleStrategy (node:internal/modules/esm/translators:106:18)
    at ModuleLoader.#translate (node:internal/modules/esm/loader:473:12)
    at ModuleLoader.loadAndTranslate (node:internal/modules/esm/loader:520:27)


error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[hejops]

I figured out that this is due to rollup-plugin-ts, which has been deprecated. @rollup/plugin-typescript seems to be the way to go these days. I'll try writing a PR to fix this.