[javascript] default prameters

default prameters

1.

function sum(value, size) {
  size = size || 1;
  return value * size
}

console.log(sum(3)); //3

2.

function sum(value, size=1) {
  return value * size
}

console.log(sum(3)); //3

3.

function sum(value, size={value:1}) {
  return value * size.value
}

console.log(sum(3)); //3
console.log(sum(3, {value:3})); //9