Why would this arrow function work?

Question

I am exploring arrow functions, I came up with this basic example, I just need to understand how the follwing works

var getServer = () => {
    if(document.getElementById('server')){
        var serverHTML = document.getElementById('server');
        serverHTML.innerHTML = "Server: " + window.location.host;
    }
    if(document.getElementById('serverxs')){
        var serverHTMLxs = document.getElementById('serverxs');
        serverHTMLxs.innerHTML = "Server: " + window.location.host;
    }
};

The getServer = () => part is confusing how is empty brackets correct? Or am I wrong.

Any documentation or answers appreciated

score 3 · Accepted Answer · edited Oct 31 '17 at 11:14

3

You can "read" arrow functions like this

(par1, par2) => "value"

turns into

function(par1, par2){ return "value"; }

So:

() =>

turns into a function with no parameters passed to it. An exception to this is when one argument is passed to an arrow function, so:

param=>{ return value; }
// turns into
function(param){ return value; }

edited Oct 31 '17 at 11:14

user7951676

377
2
10

answered Oct 31 '17 at 11:05

Luca De Nardi

2,280
16
35

Martijn · Answer 2 · 2017-10-31T11:05:34.977

1

It's a function without parameters, as short/arrow function:

var getServer = () => { /* ... */ }
// matches
var getServer = function (){ /* ... */}

// Example:
var example = function (foo, bar){ return foo;}
// matches
var example = (foo, bar) => { return foo;}

There are some caveats though, which you might want to check.

edited Oct 31 '17 at 11:05

answered Oct 31 '17 at 11:04

Martijn

15,791
4
36
68

* with all the caveats described in this post https://stackoverflow.com/questions/34361379/arrow-function-vs-function-declaration-expressions-are-they-equivalent-exch – John Oct 31 '17 at 11:05
I've added it to my post so it gets read better :) For simple functions they're the same, but it might get confusing fast. – Martijn Oct 31 '17 at 11:07
I tried using it in one of my projects but the arguments got a little confusing – Andrew Christopher Nov 01 '17 at 11:03

Why would this arrow function work?

2 Answers2