// arguments is "like" an array that stores all arguments given to manyArgs

// (User can invoke manyArgs with arguments even though none are specified)

function manyArgs() {

  for (var i = 0; i < arguments.length; ++i)

    alert(arguments[i]);

}

// Note: for arrow functions you must do

let manyArgs = (concreteArg1, concreteArg2, ...rest) => {

  for (var i = 0; i < rest.length; ++i)

    alert(rest[i]);

    // concreteArgs are not included in rest "array"

}

const myFunction = (str, id=0) => {

    console.log(str, id)

} 

myFunction("Hello Grepper")

// OUTPUT : "Hello Grepper 0"

​

myFunction("HG", 10)

// OUTPUT : "HG 10"