js 'types' can only be used in a .ts file - Visual Studio Code using @ts-check

I'm using flow with vscode but had the same problem. I solved it with these steps:

1. Install the extension Flow Language Support

2. Disable the built-in TypeScript extension:

   1. Go to Extensions tab
   2. Search for @builtin TypeScript and JavaScript Language Features
   3. Click on Disable

Use "javascript.validate.enable": false in your VS Code settings, It doesn't disable ESLINT. I use both ESLINT & Flow. Simply follow the instructions Flow For Vs Code Setup

Adding this line in settings.json. Helps "javascript.validate.enable": false

You must use a .ts file - e.g. test.ts to get Typescript validation, intellisense typing of vars, return types, as well as "typed" error checking (e.g. passing a string to a method that expects an number param will error out).

It will be transpiled into (standard) .js via tsc.

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Update (11/2018):

Clarification needed based on down-votes, very helpful comments and other answers.

types

• Yes, you can do type checking in VS Code in .js files with @ts-check - as shown in the animation

• What I originally was referring to for Typescript types is something like this in .ts which isn't quite the same thing:

  hello-world.ts

  function hello(str: string): string {
    return 1;
  }
  
  function foo(str:string):void{
     console.log(str);
  }
  

  This will not compile. Error: Type "1" is not assignable to String

• if you tried this syntax in a Javascript hello-world.js file:

  //@ts-check
  
  function hello(str: string): string {
    return 1;
  }
  
  function foo(str:string):void{
     console.log(str);
  }
  

  The error message referenced by OP is shown: [js] 'types' can only be used in a .ts file

If there's something I missed that covers this as well as the OP's context, please add. Let's all learn.