Is there a good reason to avoid FOR loops without a final-expression in JS?

Question

Is it a bad habit to write reverse loops as:

for (i = N; i--;)

in order to access (N-1) to 0

If so, why? jsLint certainly doesn't like it.

Answer 1

There's no technical reason that this won't work. However, it clearly has readability issues since someone had an immediate "well that won't work!" reaction.

This is the kind of issue that the jQuery team struggles with – whether to use novel constructs that save bytes at the expense of clarity and maintainability. It really comes down to whether it's worth 1 or 3 bytes of savings:

for(var i=9;i--;)
var i=9;while(i--)
for(var i=9;i>0;i--)

In this case, probably not.

Answer 2

It is less readable, without your explanation it would take me few seconds to understand what the loop does. Why not simply:

while(i-- > 0)

?