Arrow function with Square Brackets?

Question

I am working on some code, and I have stumbled across something I am unfamiliar with.

export const doSomething = () => [ someFunction(), bind(stuff, stuff, stuff) ]; 

I have never seen an arrow function with a square bracket like that, has anyone else? If so what is the meaning of how it works?

Answer 1

This code means that your function doSomething returns an array when

[0] element - the result of execution of function someFunction() and

[1] element - the result of execution of function bind(stuff, stuff, stuff) .

This is a shortcut for:

export const doSomething = () => {
    return [ someFunction(), bind(stuff, stuff, stuff) ]
}; 

But be careful if you want to make a shortcut for returning objects. You have to wrap objects in parentheses () , like this:

export const doSomething = () => ({ name: 'John' }) .

Answer 2

It's just returning an array.

You might use it with a destructuring assign eg

const [someResult, boundStuff] = doSomething()

Or just like any old function eg

const something = doSomething()