Typescript = Javascript + Commented Types. noImplicitAny doesn't work with jsdoc types

[nojvek]

TypeScript Version: 1.8.0 / nightly (2.0.0-dev.201xxxxx)

Code

/**
 * @param {string} cmd - command to execute
 */
function exec(cmd) {
  execSync(cmd)
}

Expected behavior:

Type of cmd should be string

Actual behavior:

Type of cmd is any and compiler gives error.

/** @type string */
const hello

Still gives no implicitError.

Weird thing is if my file is .js then tsc doesn't do any type checking or give me useful errors.

The user scenario is:

• I want to use tsc to typecheck and VSCode to provide excellent code complete/refactoring
• I don't want to transpile since I'm already using ES6. I just want the IDE experience
• I want my typescript type specific information defined as jsdoc or flow like comments.
• Typescript is Javascript + Types. It should also work for Javascript + Commented Types.

[mhegazy]

There is one way to write types in a .ts file, and that is type annotations. JSDoc comments are not relevant here. in a .js file it can be used, and it is. but --noImplicitAny is not relevant there really.

[nojvek]

So this means typescript cannot be used a pure type validator for js files. Whey do I need to write a separate .ts file when type information can be inferred from flow like comments. A big usecase is just adding types to javascript function parameters.

…

On Thu, Dec 15, 2016 at 12:54 PM, Mohamed Hegazy ***@***.***> wrote: Closed #10033 <#10033>. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#10033 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA-JVF9jFgxfHuoOjsVQwrT0ZUXYVsvuks5rIakegaJpZM4JYUy1> .

[mhegazy]

So this means typescript cannot be used a pure type validator for js files.

it can, and it does. the file extension needs to be .js.

A big usecase is just adding types to javascript function parameters.

this works in VS Code / VS 2017 today. just open a .js file add jsdoc comments and you should be able to use them. you can use them in your typescript compilation using --allowjs.

All the type errors are suppressed in a .js file, but this is tracked by #6802

[jcrben]

for posterity, it seems --noImplicitAny isn't really recommended in js per #14617 altho it's still around... looks like jsdoc annotations don't work.

bit tough for js and ts to coexist with these options but oh well