Javascript/jQuery if statement not comparing anything

Question

I'm quite new to using jQuery with Javascript and I've got a bug where I need to analyse every part of a pre-written function.

Part of this function includes an if statement seemingly without a condition and I was hoping someone would be able to explain it to me, code below.

$("a").bind("click", myFunction);

function myFunction(event) {
        if (event.target) {
       // some code
    }
}

My confusion here is what "if (event.target)" is equating to/testing as it is doesn't seem to be comparing anything. Any help or pointing towards reading material would be appreciated.

Thanks in advance!

A mouse click is an event. The document object model (DOM) element you just clicked on is the target. — zipzit
– zipzit, Commented Jan 31, 2018 at 9:56
"As of jQuery 3.0, .bind() has been deprecated. It was superseded by the .on() method for attaching event handlers to a document since jQuery 1.7" — Badiparmagi
– Badiparmagi, Commented Jan 31, 2018 at 9:57
It's due to the type coercion that JS does. Sometimes it's helpful, sometimes its a pain that you need to be aware of. See this: sitepoint.com/javascript-truthy-falsy — Rory McCrossan
– Rory McCrossan, Commented Jan 31, 2018 at 9:58
it's just checking if the event.target property of the event object will be null or not — Roljhon
– Roljhon, Commented Jan 31, 2018 at 9:58

Rory McCrossan · Accepted Answer · 2018-01-31 10:03:52Z

2

Any condition can be tested as 'falsy' or 'truthy'.

For exemple :

const iAmTruthy = true;
if (iAmTruthy) {
  console.log('the condition is fulfilled');
}

Here's a list of truthy values in JS : https://developer.mozilla.org/en-US/docs/Glossary/Truthy

Here's another example with falsy value :

const iAmTruthy = false;
if (!iAmTruthy) {
  console.log('the condition is fulfilled');
}

And a list of falsy values : https://developer.mozilla.org/en-US/docs/Glossary/Falsy

edited Jan 31, 2018 at 10:03

Rory McCrossan

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answered Jan 31, 2018 at 10:02

3Dos

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Comments

KL_ · Accepted Answer · 2018-01-31 10:03:45Z

0

What you're doing here is comparing the event.target. It will return true if the variable have some value (and has been defined), otherwise it will return false.

Note: false, 0, '', or null will return false too.

var a; //undefined
if(a){ console.log('undefined a: true'); } else { console.log('undefined a: false'); }

a = null;
if(a){ console.log('null a: true'); } else { console.log('null a: false'); }

a = 0;
if(a){ console.log('zero a: true'); } else { console.log('zero a: false'); }

a = '';
if(a){ console.log('empty string a: true'); } else { console.log('empty string a: false'); }

a = 1;
if(a){ console.log('number a: true'); } else { console.log('number a: false'); }

answered Jan 31, 2018 at 10:03

KL_

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Comments

GolezTrol · Accepted Answer · 2018-01-31 10:15:47Z

This is unrelated to jQuery, and just plain JavaScript.

The if statement condition is an expression that in the end evaluates to true or false. This can be an explicit comparison like a===b, but you can also evaluate other values that are considered to be true or false by the if statement. You're testing whether they are 'truthy' or 'falsy'.

In this particular case, you're basically testing if event.target has something assigned to it. If it has, it is truthy, otherwise it is falsy. The unwritten assumption is that if it has, it's a valid DOM element.

It's unlikely that something else was assigned to event.target, so this code just loosely checks if something is there or not, rather than checking explicitly whether that something is indeed a valid element and not, say, 15 or 'Hello world'. These kinds of assumptions are pretty common, because otherwise your code will become slow and hardly readable because of all the checks.

See Mozilla to learn more about 'truthy' and 'falsy'.

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