type argument optional typescript

1// Optional Parameters
2sayHello(hello?: string) {
3	console.log(hello);
4}
5
6sayHello(); // Prints 'undefined'
7
8sayHello('world'); // Prints 'world'

1// Optional parameter
2function foo(x?: number) {
3    console.log("x : "+ x);
4}
5foo();
6foo(6);

1
2        
3            
4        
5     function multiply(a: number, b: number, c?: number): number {
6
7    if (typeof c !== 'undefined') {
8        return a * b * c;
9    }
10    return a * b;
11}

1// Optional type parameters
2private logData<T, S = {}>(operation: string, responseData: T, requestData?: S) {
3  // your implementation here
4}
5