typescript type of generic function code example

Example 1: extend generics in functions typescript

interface Lengthwise {
    length: number;
}

function loggingIdentity<T extends Lengthwise>(arg: T): T {
    console.log(arg.length);  // Now we know it has a .length property, so no more error
    return arg;
}

Example 2: typescript generic function

function firstElement<Type>(arr: Type[]): Type {
  return arr[0];
}
// s is of type 'string'
const s = firstElement(["a", "b", "c"]);
// n is of type 'number'
const n = firstElement([1, 2, 3]);

Example 3: typescript generic type

function identity<T>(arg: T): T {
  return arg;
}Try