JAVASCRIPT

Set Default Parameter Value

	function Person(a, b={})
	{
    /*code*/
		
	}
    
    /*now, if you leave b blank, b will be {} rather than undefined*/

Default parameter

 
function addNum(a=0, b=0) {
    return a + b ;
}
 
 
console.log(addNum());              //1
console.log(addNum(1));             //1
console.log(addNum(1,2));           //3
 

Default argument values

def ask_ok(prompt, retries=4, reminder='Please try again!'):
    while True:
        ok = input(prompt)
        if ok in ('y', 'ye', 'yes'):
            return True
        if ok in ('n', 'no', 'nop', 'nope'):
            return False
        retries = retries - 1
        if retries < 0:
            raise ValueError('invalid user response')
        print(reminder)