optional interface typescript code example

Example 1: ts interface optional parameter

interface Person {
    name: string;
    age: number;
    phone?: string;
}

let p: Person = {name: "Ashlee", age: 29};
console.log(p);

Example 2: typescript interface

interface NumberOrStringDictionary {
  [index: string]: number | string;
  length: number; // ok, length is a number
  name: string; // ok, name is a string
}Try

Example 3: create method in interface for set TS

running: someTask, arg: test