As of ES6, we are able to set default parameter values when defining a function, as shown below:
function calculateBill(total, tax = 0.13, tip = 0.15) {...}
This allows for named parameters to be initialized with default values if no value is present or it evaluates to undefined
.
If you want to call a function without passing one of the parameters, allowing it to fall back to the default, you need to explicitly pass undefined
in it’s place, as shown below:
const totalBill = calculateBill(100, undefined, 0.25);
One caveat to keep in mind is that this is order-dependent (without using destructuring).
At the time of publishing this post, this feature has been around for a while and has pretty solid browser support.
References & Resources
- ES6 For Everyone – course by Wes Bos
- MDN Documentation