why we need interface in typescript code example

Example 1: typescript interface function

interface IEmployee {
    empCode: number;
    empName: string;
    getSalary: (number) => number; // arrow function
    getManagerName(number): string; 
}

Example 2: typescript interface

interface Foo {
    bar: string;
    qux: number;
}
// Creates object implementing interface:
const MyFoo = <Foo> {
    bar: "Hello",
    qux: 7
}
// Or:
const MyFoo: Foo = {
    bar: "Hello",
    qux: 7
}