create function with typescript code example

Example 1: how to make a parameter optional in typescript

// Optional parameter
function foo(x?: number) {
    console.log("x : "+ x);
}
foo();
foo(6);

Example 2: types function typescript

interface Alternate_Syntax_4_Advanced {
    title: string;
    callback<T extends unknown[], R = unknown>(...args?: T): R;
}