Enforcing arity?

Axel Rauschmayer axel at rauschma.de
Sun Jan 6 16:31:29 PST 2013

What is the simplest way of enforcing an arity in ES6? Doesn’t it involve arguments?

function add(x, y) {
    if (arguments.length !== 2) throw ...

To avoid `argument`, one could:
- ensure a maximum arity by adding a ...rest parameter and checking that its length is 0.
- ensure a minimum arity, by giving y a default value and checking for it.

Would fail-fast destructuring work?

function add(...args) {
    let [x,y] = args;

Dr. Axel Rauschmayer
axel at rauschma.de

home: rauschma.de
twitter: twitter.com/rauschma
blog: 2ality.com

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