Null value in jQuery.get doesn't allow use of dataType

[jcubic]

Description

According to jQuery.get documentation you can use null as success function to be able to use dataType. But it seems that it's not working. The only way to get text from JSON response is to use $.noop. So this need to be fixed or documentation needs to be updated.

I use jQuery 3.6.0.

Link to test case

await $.get("https://httpbin.org/json", null, "text")
await $.get("https://httpbin.org/json", $.noop, "text")

https://jsbin.com/safuliduje/edit?html,css,js,output

[mgol]

Thanks for the report. Can you provide a test case on JS Bin as the issue template requested? Thanks!

[jcubic]

@mgol Added link.

[mgol]

OK, it looks like the current implementation allows you to provide null as a placeholder for the callback but doesn't allow you to skip the data parameter then. This means the following:

await $.get("https://httpbin.org/json", null, "text");

doesn't work as expected but the following:

await $.get("https://httpbin.org/json", null, null, "text");

does. With hindsight, all of these short forms of jQuery.ajax with their positional parameters were a mistake as there's always a lot of parameter juggling. Perhaps we should update the doc that if you provide null for the callback then you also need to provide the data parameter, even if null or undefined.

We could also update the implementation to handle this case as well but that wouldn't fix all those past versions anyway so I'm not sure if it's worth it; we'd need to update the docs as well anyway.

Thoughts, @jquery/core?

[gibson042]

Even though parameter hockey isn't great and we don't want to encourage the pattern, I think it's worth fixing code to match documentation. The interesting cases are those with parameter gaps, and since dataType is documented to require success (excluding jQuery.get(url, data, dataType) and jQuery.get(url, dataType)), those are limited to missing data (i.e., jQuery.get(url, fnOrNull, strOrUndef)).

AFAICT, we just need to update if ( typeof data === "function" ) in the definition of jQuery.{get,post} to include an alternative such as || data == null or || data === null.

[mgol]

PR: #5139.