Declaring multiple variables in JavaScript

Question

In JavaScript, it is possible to declare multiple variables like this:

var variable1 = "Hello, World!";
var variable2 = "Testing...";
var          


        

Answer 1

Although both are valid, using the second discourages inexperienced developers from placing var statements all over the place and causing hoisting issues. If there is only one var per function, at the top of the function, then it is easier to debug the code as a whole. This can mean that the lines where the variables are declared are not as explicit as some may like.

I feel that trade-off is worth it, if it means weaning a developer off of dropping 'var' anywhere they feel like.

People may complain about JSLint, I do as well, but a lot of it is geared not toward fixing issues with the language, but in correcting bad habits of the coders and therefore preventing problems in the code they write. Therefore:

"In languages with block scope, it is usually recommended that variables be declared at the site of first use. But because JavaScript does not have block scope, it is wiser to declare all of a function's variables at the top of the function. It is recommended that a single var statement be used per function." - http://www.jslint.com/lint.html#scope