JSLint

I thought I have written about this cool tool long time ago. However, when I tried to search for it, I could not find it. So, not searchable means "I have not written about it yet". Here we go.

JSLint, a tool written by Douglas Crockford, has saved a lot of my time as I develop the client-side functions of Fablusi. It checks for common Javascript coding errors and warns a number of "tolerated" practices.

Dean Edwards points out that JSLint is not a silver bullet in JSLint Considered Harmful which I will respectfully disagree.

I don't like the mandatory braces on if statements. I've become rather fond of one-liners like this:

function foo( x ) {
if( ! x ) return;
// now process x
}

This one-liner will create error when you want to compact the javascript by removing the white spaces!

JSLint's prohibition against repeated "var" declarations can lead to fragile code:

function foo() {
for( var i = 0; i < a.length; i++ ) {
}
// and later in the function:
for( i = 0; i < b.length; i++ ) {
}
}

If you later refactor that code, it would be easy to forget to put the "var" back in.

I would rewrite the code like this:

function foo() {
var i=0;
for( i = 0; i < a.length; i++ ) {
}
// and later in the function:
for( i = 0; i < b.length; i++ ) {
}
}

This will not generate a warning by JSLint and it is a good practice! Re: refactoring - we should put the var in anyway! JSLint will warn you if you have forgotten!

As pointed out by Dominic Mitchell is his post JSLint Backlash, ‘Considered Harmful’ Essays Considered Harmful.