Why is it possible to add a number and an array?

Question

typescript

typescript is a strongly typed language. That is, it does not allow type conversion during the operation. However, the following code does not throw any error messages:

const multy = ( a, b ) => a + b;

const number = 5;
const array = [ 0, 1, 2 ];

const result1 = multy( number, array[ 2 ] );
const result2 = multy( number, array );

console.log(result1, typeof result1)
console.log(result2, typeof result2)

Conclusion:

7 "number"
50,1,2 string

I thought that only javascript allows you to add a number and an array and get a string as an output, but typescript does not. But the code says otherwise. Please tell me where I'm wrong.

Answer 1

Well, add types to multy arguments and you will be happy. And then you drown for the typescript, but I don’t see a single type in the code.

Answer 2

Typescript is a language with weak static typing.
The tsconfig config allows you to configure the compiler in different ways - it can be configured so that it will only inform about errors and compile the code anyway. Google for keywords emit on error. And no implicit any, google it too.