Typescript TSX and generic parameters

To get it to understand it's a type parameter and not a JSX element, you can add a comma after the type parameter:

const f = <T1,>(arg1: T1) => <T2,>(arg2: T2) => {
   return { arg1, arg2 };
};

Or you could use function expressions instead:

const f = function<T1>(arg1: T1) {
    return function<T2>(arg2: T2) {
        return { arg1, arg2 };
    };
};

Or alternatively, in this scenario, this works:

const f = <T1, T2>(arg1: T1) => (arg2: T2) => {
   return { arg1, arg2 };
};

This is a result of parsing ambiguity issues. One thing that would make this unambiguous is adding an explicit constraint on T1.

const f = <T1 extends unknown>(arg1: T1) => {
    return { arg1 };
}

Type parameters like T1 implicitly have a constraint of unknown anyway, so in this case your code is functionally equivalent.

Take this solution and you can apply on each arrow function from your original example.

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