Passing undefined to .text() does not trigger setter

[Xavi]

Passing undefined to $.fn.text() triggers getter functionality instead of the setter functionality. For example the following code throws an exception:

var text;
$("<div/>").text(text).append($("<span/>"))

[Rick Waldron]

This is expected behaviour.

[Xavi]

Pull request with fix: ​https://github.com/jquery/jquery/pull/392

[Xavi]

Why is it expected behavior? It breaks chaining and causes unexpected exceptions.

[Rick Waldron]

It's expected that the developer knows to test their own variables before passing them to methods that have overloaded signatures.

var text;
$("<div/>").text( text || "" ).append($("<span/>"))

​http://jsfiddle.net/rwaldron/sTesj/

The code above will work fine without breaking the existing api.

[Rick Waldron]

As noted on the pull request: ​http://api.jquery.com/text/ The documentation specifies the valid input to the method and their expected outcome.

[Xavi]

FWIW, I would recommend using this work around instead:

var text;
$("<div/>").text( text + "" ).append($("<span/>"));

It handles 0 and null better and saves 1 byte.

Also, FWIW, this bug also affects $.fn.html, $.fn.attr, $.fn.width, $.fn.height, and number other functions.

I replied to ​http://bugs.jquery.com/ticket/5571, but it might be worth repeating my argument here. Basically, I feel that the getter/setter functionality should be determined by arguments.length instead of the argument values. IMO, this leads to a more consistent API and is less surprising to the user.

There is the argument that undefined is an invalid value, so breaking the chain makes sense since it acts like a form of error reporting. I disagree with this logic. As a form of error reporting, breaking the chain doesn't always work and leads to confusing error messages. (See ticket for more detailed explanation).

[Timmy Willison]

#9826 is a duplicate of this ticket.

[TJ Holowaychuk]

I agree that this is a bug, arity > 1 shows the intention

[Rick Waldron]

#10396 is a duplicate of this ticket.

[Timmy Willison]

#10671 is a duplicate of this ticket.

[Rick Waldron]

#10749 is a duplicate of this ticket.

[dmethvin]

Reopening for 1.8 discussion -- should we have uniform behavior for .method(undefined/null) ?

[dmethvin]

We landed this space-saving bug fix in ​https://github.com/jquery/jquery/commit/6c2a501de40a5f6b3ad382e2d309e5a10fce04d0

[DNS]

text + ""

text || ""

Note that these two have different behavior in cases other than those you've considered. If text is an empty array, for example, the previous effective value would have been [], while in jQuery 1.7.2 it becomes "[object Object]".

It appears that .text([]) is a no-op in jQuery pre-1.7.2. Some of my code was unknowingly relying on this behavior, and broke when I upgraded to 1.7.2. I'm fixing the code in question, which shouldn't be passing [] to text() in the first place. But I figured you might want to know about this, since it does represent an undocumented change, however minor.