Flag 'importsNotUsedAsValues' is deprecated and will stop functioning in TypeScript 5.5

[gornostay25]

READ HERE HOW TO FIX IT

#8650 (comment)

Bug report

Describe the bug

My VScode show this in problems tab

Flag 'importsNotUsedAsValues' is deprecated and will stop functioning in TypeScript 5.5. Specify 'ignoreDeprecations: "5.0"' to silence this error.
  Use 'verbatimModuleSyntax' instead.

.svelte-kit/tsconfig.json

{
	"compilerOptions": {
		"paths": {
			"$lib": [
				"../src/lib"
			],
			"$lib/*": [
				"../src/lib/*"
			]
		},
		"rootDirs": [
			"..",
			"./types"
		],
/////////////////////////////////////////////////////////////////////
		"importsNotUsedAsValues": "error",
/////////////////////////////////////////////////////////////////////
		"isolatedModules": true,
		"preserveValueImports": true,
		"lib": [
			"esnext",
			"DOM",
			"DOM.Iterable"
		],
		"moduleResolution": "node",
		"module": "esnext",
		"target": "esnext"
	},
	"include": [
...
	],
	"exclude": [
...
	]
}

Reproduction

"devDependencies": {
    "@sveltejs/adapter-cloudflare": "^1.1.0",
    "@sveltejs/kit": "^1.2.2",
    "@typescript-eslint/eslint-plugin": "^5.48.2",
    "@typescript-eslint/parser": "^5.48.2",
    "eslint": "^8.32.0",
    "eslint-config-prettier": "^8.6.0",
    "eslint-plugin-svelte3": "^4.0.0",
    "prettier": "^2.8.3",
    "prettier-plugin-svelte": "^2.9.0",
    "svelte": "^3.55.1",
    "svelte-adapter-bun": "file:../svelte-adapter-bun",
    "svelte-check": "^3.0.2",
    "tslib": "^2.4.1",
    "typescript": "^4.9.4",
    "vite": "^4.0.4",
    "wrangler": "^2.8.0"
  },

Logs

No response

System Info

System:
    OS: Windows 10 10.0.22621
    CPU: (8) x64 Intel(R) Core(TM) i5-8250U CPU @ 1.60GHz
    Memory: 1.79 GB / 7.91 GB
  Binaries:
    Node: 19.4.0 - C:\Program Files\nodejs\node.EXE
    npm: 8.19.3 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Spartan (44.22621.1105.0), Chromium (109.0.1518.49)
  npmPackages:
    @sveltejs/adapter-cloudflare: ^1.1.0 => 1.1.0
    @sveltejs/kit: ^1.2.2 => 1.2.2
    svelte: ^3.55.1 => 3.55.1
    vite: ^4.0.4 => 4.0.4

Severity

annoyance

Additional Information

No response

[Rich-Harris]

Weird, I have the latest VSCode with TypeScript 4.9.4 (same as your version, according to your npxinfo) and I'm not seeing this. If I change it to verbatimModuleSyntax I do get an error. Are there any other steps to reproduce?

[dummdidumm]

Likely because OP is using the beta version of TS 5.0, where that flag is introduced.
I'm not sure how to proceed. I think the safest would be to switch this for SvelteKit 2.0 while bumping the minimum required TS version. I believe vite/esbuild both use that now deprecated flag for compilation, so directly changing it likely breaks things

[gornostay25]

@Rich-Harris

[thenbe]

@gornostay25 If you right click the bottom right corner (next to where it says prettier), does it show you more info about your typescript setup?

[dummdidumm]

I guess another thing is to add said ignoreDeprecations flag. I'm not sure if we can add that for 4.9 without it being an error, we'd need to test that out.

That flag is still available until 5.5, which is more than one year from now. I suspect we have SvelteKit 2.0 by then at which point we can switch flags.

[gornostay25]

@ambiguous48

[engageintellect]

Getting the same error when init-ing Tailwind to a fresh "npm create svelte@latest"

[petermekhaeil]

Related: microsoft/TypeScript#52203

[jrmoynihan]

For anyone who has the 5.0.0 beta version installed in VSCode, you can simply swap the workspace over to 4.9.4 to remove the errors for now:

Click the TS banner in your status bar, then "Switch Version":

Select v4.9.x for the workspace:

[orbh]

For me error was removed after disabling the JavaScript and TypeScript Nightly extension in VS Code. But yeah you could probably also change the TS-version in your workspace.