prefer-boolean-length-check

Prefers using a boolean length check rather than comparing against zero.

Examples of incorrect code for this rule:

if (foo.length == 0) {}
if (foo.length > 0) {}
if (foo && foo.length == 0) {}
function bar() { return foo.length > 0 }

Examples of correct code for this rule:

if (foo.length && foo.length) {}
if (!foo.length) {}
var a = foo.length > 0
function bar() { return !!foo.length }