Prettier and ESLint in VS Code crash svelte compiler

Describe the bug With this template where we want ESLint to co exist with prettier I have 2 problems when the plugins are nebale with this config

As described in the prettier docs this enable ESLint to call prettier

1. Lint crashes in the svlte compile - see stack trace
2. Prettier fails to format on save the App.svelte file - and error flashes up in the status bar

Logs see stack trace

To Reproduce Uncommented the line aboveand comment the one above it

1. Run npm run lint from the command line
2. edit the App.svelte and save the file

Expected behavior

1. no error and llinter succeeds
2. File is reformated via prettier

Stacktraces

Stack trace

$ npm run lint

svelte-project@1.0.0 lint C:\projects\svelte-code-cypress-project eslint src/*

ParseError: Expected } 1 | export let name 2 |

3 | {name;name=0} | ^ Occurred while linting C:\projects\svelte-code-cypress-project\src\App.svelte:3 at error$1 (C:\projects\svelte-code-cypress-project\node_modules\svelte\compiler.js:13329:20) at Parser$2.error (C:\projects\svelte-code-cypress-project\node_modules\svelte\compiler.js:13405:10) at Parser$2.eat (C:\projects\svelte-code-cypress-project\node_modules\svelte\compiler.js:13419:19) at mustache (C:\projects\svelte-code-cypress-project\node_modules\svelte\compiler.js:13220:17) at new Parser$2 (C:\projects\svelte-code-cypress-project\node_modules\svelte\compiler.js:13364:22) at Object.parse$1 [as parse] (C:\projects\svelte-code-cypress-project\node_modules\svelte\compiler.js:13495:21) at Object.parse (C:\projects\svelte-code-cypress-project\node_modules\prettier-plugin-svelte\plugin.js:669:51) at Object.parse$2 [as parse] (C:\projects\svelte-code-cypress-project\node_modules\prettier\index.js:10629:19) at coreFormat (C:\projects\svelte-code-cypress-project\node_modules\prettier\index.js:13888:23) at format (C:\projects\svelte-code-cypress-project\node_modules\prettier\index.js:14146:73) npm ERR! code ELIFECYCLE npm ERR! errno 2 npm ERR! svelte-project@1.0.0 lint: eslint src/* npm ERR! Exit status 2 npm ERR! npm ERR! Failed at the svelte-project@1.0.0 lint script. npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in: npm ERR! C:\Users\steve\AppData\Roaming\npm-cache_logs\2019-09-11T17_00_42_583Z-debug.log

Information about your Svelte project:

• Your browser and the version: (e.x. Chrome 52.1, Firefox 48.0, IE 10) Not relevant - build error

• Your operating system: (e.x. OS X 10, Ubuntu Linux 19.10, Windows XP, etc) Windows 10 latest 1903

• Svelte version (Please check you can reproduce the issue with the latest release!) 3.12.1

• Whether your project uses Webpack or Rollup Roll up

Severity How severe an issue is this bug to you? Is this annoying, blocking some users, blocking an upgrade or blocking your usage of Svelte entirely?

Serious - can’t lint or run prettier on svelte files

Additional context Add any other context about the problem here.

[toerndev]

@Conduitry Sorry let me rephrase! I’m looking for the maintainers’ technical opinion on the possibility of having the eslint plugin working on the whole file instead. If the maintainers are open to explore the idea, it’s more enticing to start trying to solve it. 😃

No I get that the Prettier plugin isn’t official and that maybe noone in the Svelte team uses Prettier, and am not asking your to prioritize it although I’m sure tons of newcomers will want this support… 😉 There’s also the question of whether plugins are behaving as expected within the larger javascript & eslint ecosystem. How the eslint plugin might/should work, given enough development. Thus the question in my last reply about an alternative approach.

[SteveALee]

it although I’m sure tons of newcomers will want this support… 😉

I’d like to add my support to this, at least as a single newcomerto svelte. My workflow always included prettier to reformat my messy editing on file save. So it was natural to continue to use it for the JS part of svelte files.

I get that svelte files are NOT javascript but a compiled super set and that might lead to some issues but in general I want prettier to continue to work. In fact I doubt there will be any issues as Richard was careful to overload existing JS syntax for all new features - eg labels