JavaScript naming conventions with underscore

Question

In this SO question, the answerer uses an underscore on line 3. If it were simply the start of a variable name, I'd be good with that. But what does _(row) mean?

the question is answered right in his post and you commented on it. What's the point of posting this? — Cfreak, May 02 '12 at 20:51
Oh, I see. It's another JavaScript library called underscore. — Phillip Senn, May 02 '12 at 20:53

score 4 · Answer 1 · answered May 02 '12 at 20:50

It is the start of a variable name. It is also the end of a variable name. The variable (which has a function assigned to it) is _. The question references underscore.js, which provides it.

Try, for example:

function _() { 
    alert('underscore!'); 
};
console.log(typeof _);
console.log(_);
_();

Welcome to the wonderful world of completely unintuative variable names that are used because they are short and not alphanumeric. See also $, beloved of Prototype, jQuery and Mootools. In counterpoint, see Self-documenting (code) on Wikipedia.

Thanks Quentin! I've heard of the underscore library in passing, but have never taken the time to read anything about it. — Phillip Senn, May 02 '12 at 21:18

score 3 · Accepted Answer · answered May 02 '12 at 20:50

3

The _ is underscore.js. _ is a variable, it's a function, so you can do _(rows).

In JavaScript, you can name variables whatever you want. Such as $ (jQuery) and _.

answered May 02 '12 at 20:50

gen_Eric

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OK, thanks Rocket! If I have jQuery loaded, I don't think I need underscore. It looks like I can process it with the jQuery each command. – Phillip Senn May 02 '12 at 21:19

JavaScript naming conventions with underscore

2 Answers2