Let the compiler shout at me on typeerrors: about typescript

[NobbZ]

PS: totally the same behaviour when s/string/number/

[NobbZ]

OK, in the meantime I was able to find out, that tsc will complain about a syntax error:

hello-world.ts(2,33): error TS1005: ',' expected.

After some googling I found that correct syntax for the class were:

class HelloWorld {
    static hello(name: number = "World"): number {
        return "Hello, " + name + "!"
    }
}

compiling this, now successfully complains about types beeing incorrect:

hello-world.ts(2,18): error TS2322: Type '"World"' is not assignable to type 'number'.
hello-world.ts(3,9): error TS2322: Type 'string' is not assignable to type 'number'.
hello-world.test.ts(11,29): error TS2345: Argument of type '"Bob"' is not assignable to parameter of type 'number'.
hello-world.test.ts(15,29): error TS2345: Argument of type '"Sally"' is not assignable to parameter of type 'number'.

Therefore I have to assume, that the typescript-track currently doesn't even use typescript!

[masters3d]

Good point. I filed a bug/feature question.
As a work around we could run the compiler every time we run the tests to catch this
"test": "tsc -p . && jest --no-cache",
I do think since ts-jest compiles the code before running jest that they should display any errors from the compiler and fail.

[NobbZ]

You filed a bug/feature where? Do you have a link/crossref?

[masters3d]

kulshekhar/ts-jest#250

[NobbZ]

Also, a better way to alter the script line seems to be: tsc --noEmit -p . && jest --no-cache.

This way there is no javascript generated which leads to running the tests twice by jest

[masters3d]

What rabbit hole. Others are also using --noEmit. I think that is what we are going to use too: ds300/react-native-typescript-transformer#13

[thedevelopnik]

@masters3d thanks for doing that PR! Looks like a good solution.

And thanks for catching this @NobbZ. Just implemented the tsc --noEmit in my own copy of the exercises and found out my Hello World solution didn't pass anymore hah.