CODEWITHSUNDEEP
jqueryjson
Malte Skoruppa
Malte Skoruppa

Reputation: 1242

Proper way of calling $.getJSON?

I'm confused about the "clean" way to call $.getJSON.

According to the documentation, the synopsis is:

jQuery.getJSON( url [, data ] [, success ] )

where data is "a plain object or string that is sent to the server with the request", and success is "a callback function that is executed if the request succeeds".

In my experience, the data argument is often not needed in practice, in which case I call $.getJSON as

$.getJSON( some_url, {}, function(response) { /* do something */ });

That is, I simply pass an empty object as data. However, I've also seen people use

$.getJSON( some_url, function(response) { /* do something */ });

This is confusing, since it looks like the callback function is being passed as the data object. Yet it seems to work just fine.

How come this works? Is jQuery "clever" enough to understand the second syntax, even though it doesn't strictly correspond to the specification? Is there effectively some difference in what happens in those two calls? Between the two, is there a preferred way?

Upvotes: 3

Views: 341

Answers (2)

Lightness Races in Orbit
Lightness Races in Orbit

Reputation: 385144

Is jQuery "clever" enough to understand the second syntax,

Yes; there is code inside getJSON to detect the types of its arguments and sort it out that way.

even though it doesn't strictly correspond to the specification

It does. The synopsis you quoted explicitly says exactly that! Square brackets ([]) in synopses indicate optional arguments. In this case, both arguments are independently optional: you may provide either, or both, or neither.

Is there effectively some difference in what happens in those two calls?

No.

Between the two, is there a preferred way?

No.

Upvotes: 4

Undefined
Undefined

Reputation: 11431

The best way I have found to use $.getJSON without any parameters is like this

$.getJSON('path/to/json.json')
    .done(function(response) {
        console.log(response);
    });

Using deferred's is preferable to using callbacks in almost all circumstances.

This question is a particular favorite of mine to explain why you should choose the deferred syntax -> Asynchronous JavaScript - Callbacks vs Deferred/Promise

Upvotes: 3

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