CODEWITHSUNDEEP
typescriptvisual-studio-code
Liam
Liam

Reputation: 965

Typescript on .js file with vscode

Generally I want to write .js files with typescript instead of Flow. I configured the webpack to use ts-loader on js extension, and that works just fine. I use checkJs on tsconfig file and it check the js file fine.

However, VS Code shows an error the error on js files:

Type annotations can only be used in TypeScript files.

Screenshot of Error

How can I make that error go away in VS Code?

Upvotes: 3

Views: 2880

Answers (4)

jony89
jony89

Reputation: 5367

Since Typescript 3 is out, and the work they have done allowing it to be combined with babel 7, it makes sense now for many programmers to have typescript in .js files.

Currently I have added the following vscode settings :

"files.associations": {
    "*.js": "typescript"
},

And restarted VSCode, and it works for me.

Hopefully vscode will provide a cleaner solution in the future.

Upvotes: 2

Matt Bierner
Matt Bierner

Reputation: 65613

Yes you generally should use the correct file extension but you can force VS Code to treat JS files as TypeScript by setting:

"files.associations": {
    "*.js": "typescript"
}

Upvotes: 3

gawicks
gawicks

Reputation: 1964

You cannot use typescript type declarations in js files. (Even with checkJS enabled)

On JS files you have to use JSDoc annotations. 

/** @type {number} */
var x;

Typescript would check these for you.

But I guess what you're looking for is a .ts file

Upvotes: 5

TLP
TLP

Reputation: 1288

You should use .ts, not .js files for TypeScript code in order to get full IDE and other tooling support. The compiler will transform your .ts files into .js.

Upvotes: 0

Related Questions