Experimental decorators warning in TypeScript compilation

Question

I receive the warning...

Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option `to remove this warning.

... even though my compilerOptions in tsconfig.json have the following settings:

"emitDecoratorMetadata": true,
"experimentalDecorators": true,

What is weird is that some random classes that use decorators do not show that warning but the rest in the same project do.

What could cause such behavior in the TypeScript compiler?

Answer 1

Although VS Code is a great editor for TypeScript projects, it needs a kick every now and again. Often, without warning, certain files cause it to freak out and complain. Mostly the fix seems to be to save and close all open files, then open tsconfig.json. After that you should be able to re-open the offending file without error. If it doesn't work, lather, rinse, and repeat.

If your tsconfig.json specifies its source files using the files array, IntelliSense will only function correctly if the file in question is referenced such that VS Code can find it by traversing the input file tree.

Edit: The 'reload window' command (added ages ago now) should solve this problem once and for all.

Answer 2

I've to add the following in the settings.json file of vscode to remove the warning.

"javascript.implicitProjectConfig.experimentalDecorators": true

VSCode -> Preferences -> Settings

UPDATE

As Clepsyd pointed out, this setting had been deprecated. You need to use now

"js/ts.implicitProjectConfig.experimentalDecorators":true

Answer 3

File -> Preferences -> Settings

Answer 4

This error also occurs when you choose "src" folder for your workspace folder.

When the root folder, folder where the "src", "node_modules" are located is chosen, the error disappears

Answer 5

Please follow the below step to remove this warning message.

Step 1: Go to setting in your IDE then find or search the experimentalDecorators.

Step 2: then click on checkbox and warning has been remove in your page.

Thank you Happy Coding ..........

Answer 6

inside your project create file tsconfig.json , then add this lines

{
    "compilerOptions": {
        "experimentalDecorators": true,
        "allowJs": true
    }
}

Answer 7

In VSCode, Go to File => Preferences => Settings (or Control+comma) and it will open the User Settings file. Search "javascript.implicitProjectConfig.experimentalDecorators": true and then check the checkbox for experimentalDecorators to the file and it should fix it. It did for me.

Answer 8

have to add typescript.tsdk to my .vscode/settings.json:

"typescript.tsdk": "node_modules/typescript/lib"

Answer 9

For me, this error "Experimental support for decorators is a feature that is subject to change in a future release. (etc)" only happened in VS Code in an Angular project and only when creating a new Service.

The solution above: "In Visual Code Studio Go to File >> Preferences >> Settings, Search "decorator" in search field and Checking the option JavaScript › Implicit Project Config: Experimental Decorators" solved the problem.

Also, stopping the ng serve in the terminal window and restarting it made the error disappear after recompile.

Answer 10

In Visual Code Studio Go to File >> Preferences >> Settings, Search "decorator" in search field and Check the option as in image.

Answer 11

I get this warning displayed in vscode when creating a new Angular service with the

@Injectable({
  providedIn: 'root'
})

syntax (rather than providing the service in app.module.ts).

The warning persists until I reference the new service somewhere in the project. Once the service gets used the warning goes away. No typescript configuration or vscode settings changes necessary.

Answer 12

Open settings.json file in the following location <project_folder>/.vscode/settings.json

or you can open the file from the menu as mentioned below

VSCode -> File -> Preferences -> Workspace Settings

Then add the following lines in settings.json file

{
    "typescript.tsdk": "node_modules/typescript/lib",
    "enable_typescript_language_service": false
}

That's all. You will see no warning/error regarding 'experimentalDecorators'

Answer 13

"javascript.implicitProjectConfig.experimentalDecorators": true

Will solve this problem.

Answer 14

This answer is intended for people who are using a Javascript project and not a Typescript one. Instead of a tsconfig.json file you may use a jsconfig.json file.

In the particular case of having the decorators warning you wan write inside the file:

{
    "compilerOptions": {
        "experimentalDecorators": true
    }
}

Fort the buggy behaviors asked, it's always better to specify the "include" in the config file, and restart the editor. E.g.

{
    "compilerOptions": {
        "target": "ES6",
        "experimentalDecorators": true
    },
    "include": [
        "app/**/*"
    ],
    "exclude": [
        "node_modules"
    ]
}

Answer 15

Add following lines in tsconfig.json and restart VS Code.

{
    "compilerOptions": {
        "experimentalDecorators": true,
        "target": "es5",
        "allowJs": true
    }
}

Answer 16

I had this problem recently under Visual Studio 2017 - turned out it was caused by a "feature" of VS - ignoring tsconfig.json when Build action is not set to Content.

So changing the Build action to Content and reloading the solution solved the problem.

Answer 17

Not to belabor the point but be sure to add the following to

• Workspace Settings not User Settings

under File >> Preferences >> Settings

"javascript.implicitProjectConfig.experimentalDecorators": true

this fixed the issue for me, and i tried quite a few suggestions i found here and other places.

Answer 18

1. Open VScode.
2. Press ctrl+comma
3. Follow the directions in the screen shot
   1. Search about experimentalDecorators
   2. Edit it

Answer 19

If you are using cli to compile *.ts files, you can set experimentalDecorators using the following command:

 tsc filename.ts --experimentalDecorators "true"

Answer 20

For the sake of clarity and stupidity.

1) Open .vscode/settings.json.

2) Add "typescript.tsdk": "node_modules/typescript/lib" on it.

3) Save it.

4) Restart Visual Studio Code.

Answer 21

If you are working in Visual studio. You can try this fix

1. Unload your project from visual studio
2. Go to your project home directory and Open "csproj" file.

3. Add TypeScriptExperimentalDecorators to this section as shown in image

   

   4. Reload the project in Visual studio.

see more details at this location.

Answer 22

Please check you oppened in your VS Code the folder of the entire project and not only the src folder, because if you open only the src, then ts.config.json (located in the project folder) file will not be in scope, and VS will not recognize the experimental decorators parameters.

In my case this fixed all the problems related to this issue.

Answer 23

I had this error with following statement

Experimental support for decorators is a feature that is subject to change in a future release. Set the 'experimentalDecorators' option in your tsconfig or jsconfig to remove this warning.ts(1219)

It was there because my Component was not registered in AppModule or (app.module.ts) i simply gave the namespace like

import { abcComponent } from '../app/abc/abc.component';

and also registered it in declarations

Answer 24

I faced the same issue while creating an Injectable Services in Angular 2. I have all the things at place in tsconfig.json .Still I was getting this error at ColorsImmutable line.

@Injectable()
export class ColorsImmutable {

And fix was to register the Service at module Level or Component Level using the providers array.

providers:[ColorsImmutable ],

Answer 25

Open entire project's folder instead of project-name/src

tsconfig.json is out of src folder

Answer 26

If you using Deno JavaScript and TypeScript runtime and you enable experimentalDecorators:true in tsconfig.json or the VSCode ide settings. It will not work. According to Deno requirement, you need to provide tsconfig as a flag when running a Deno file. See Custom TypeScript Compiler Options

In my particular case I was running a Deno test and used.

$ deno test -c tsconfig.json

If it is a file, you have something like

 $ deno run -c tsconfig.json mod.ts

my tsconfig.json

{
  "compilerOptions": {
    "allowJs": true,
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "module": "esnext"
  }
}

Answer 27

I corrected the warning by removing "baseUrl": "", from the tsconfig.json file

Answer 28

You might run into this issue if you open a TS file that exists outside of the project. For instance, I'm using lerna and had a file open from another package. Although that other package had it's own tsconfig with experimental decorators, VsCode doesn't honor it.

Answer 29

You can run with this code

 tsc .\src\index.ts --experimentalDecorators "true" --emitDecoratorMetadata "true"

Answer 30

in my case I solved this issue by setting "include": [ "src/**/*"] in my tsconfig.json file and restarting vscode. I've got this solution from a github issue: https://github.com/microsoft/TypeScript/issues/9335