JS Convention for Null/Empty Checks

This:

if (value) {
}

will evaluate to false if value is null, undefined, NaN, an empty string, 0, or false.

So you should never need to do any of the following:

if (value == null) {
}
if (value == undefined) {
}
if (value == "") {
}
if (someString.length == 0) {
}

The common JS version of all these is simply

if (value) {
}

It makes for cleaner code and smaller files, too.