Default function parameters

The default function parameters in ES6, gives us the ability to initialize the function arguments with default values in case if they are undefined. For example,

function mult(a, b) {
  b = typeof b !== 'undefined' ?  b : 1;
  return a*b;
}
mult(5); // 5

function multiply(a, b = 1) {
  return a*b;
}
mult(5); // 5

Also Read:

1. position:absolute
2. JavaScript Promises - Visualized
3. window vs document
4. imperative vs declarative/functional programming
5. Understanding callbacks in javascript