What is the syntax for Typescript arrow functions with generics?

Edit

Per @Thomas comment, in newer TS compilers, we can simply do:

const foo = <T,>(x: T) => x;

The full example explaining the syntax referenced by Robin... brought it home for me:

Something like the following works fine:

function foo<T>(x: T): T { return x; }

However using an arrow generic function will not:

const foo = <T>(x: T) => x; // ERROR : unclosed `T` tag

Workaround: Use extends on the generic parameter to hint the compiler that it's a generic, e.g.:

const foo = <T extends unknown>(x: T) => x;

I found the example above confusing. I am using React and JSX so I think it complicated the scenario.

I got clarification from TypeScript Deep Dive, which states for arrow generics:

Workaround: Use extends on the generic parameter to hint the compiler that it's a generic, this came from a simpler example that helped me.

    const identity = < T extends {} >(arg: T): T => { return arg; }

This works for me

const Generic = <T> (value: T) => {
    return value;
}

If you're in a .tsx file you cannot just write <T>, but this works:

const foo = <T, >(x: T) => x;

As opposed to the extends {} hack, this hack at least preserves the intent.