CODEWITHSUNDEEP
typescript
Chris
Chris

Reputation: 8412

Configure typescript to stop failing compilation if import is not used

I've google but I can't quite find out how to tell the Typescript compiler to stop failing compilation when I import a dependency but don't use it.

Commenting out code for comparison is something I frequently do and having to delete/comment out the corresponding imports has become a bit of a pain, especially when most times I'll add the code back a few seconds later.

Can anyone tell me how to do this?

I'm using create-react-app-typescript.

Upvotes: 1

Views: 2777

Answers (4)

dogakorkmaz
dogakorkmaz

Reputation: 129

General Knowledge & Problem Cause

Typescript warnings that comes from strict-rules family won't cause your application to fail when building, Typescript errors are there to warn you about possible bugs in your script and make your code cleaner than plain Javascript.

Typescript warns you about unused imports in your file because in your tsconfig.json file option noUnusedLocals is set to true, this means a local variable* must be read|written|exported from the script that uses or initializes it.

Ways to fix it

Comment Configurations

  • You can use @ts-expect-error at one line above the error, this would do but in the future, if there is a possibility that said variable will be used in the same file, this line would throw yet another error
  • You can use @ts-ignore at one line above the error, this will result in same behavior with @ts-expect-error but even though variable used in the future, this would do nothing

JSON configuration (global configuration)

Editing JSON configuration will result in global update, that means unlike comment configurations, this will affect every (not every, see include option) typescript file in your project

Go to your projects tsconfig.json file (probably at the root of your project), find noUnusedLocals key and set its value to false

You do not need to set property noUnusedParameters to false, it has nothing to do with this error.

PS: This answer doesn't provide any different solution from other answers, its purpose is to make the given solutions more readable/understandable by providing some information about the cause of the error.

Upvotes: 0

basarat
basarat

Reputation: 276239

I frequently do and having to delete/comment out the corresponding imports has become a bit of a pain, especially when most times I'll add the code back a few seconds later.

Live with the options and errors

Its okay to have TypeScript errors as you still get output JavaScript (with default options). The errors exist just to make sure you don't commit and cause confusion for others.

Alternatively

Don't recommend this but here you go:

Silence errors

Use //@ts-ignore to silence the error.

Change the options

You can change the tsconfig options i.e. "noUnusedLocals": false, as well as "noUnusedLocals": false,.

Upvotes: 0

Vichyssoise
Vichyssoise

Reputation: 21

Set compiler option in 'tsconfig.json'.

{
  "compilerOptions": {
    ...
    "noUnusedLocals": false,
    "noUnusedParameters": false
  }
}

Upvotes: 2

Matt Evans
Matt Evans

Reputation: 7575

There is now support for @ts-ignore. This appears to be merged into the master branch, but not sure which TS release its available in, so in theory, this should work:

// @ts-ignore: unused
/// <reference path="../scripts/typedefinitions/royalslider.d.ts" />

Upvotes: 0

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