Closure compiler warning on for loop

Question

I'm using a somewhat unconventional for loop that works well for what I'm doing as paraphrased below (not bothering to show variable declarations):

if (arr && arr.length > 0) {
    for (i = arr.length; i--; i) {
        element = arr.pop();
        //rest of code
    }
}

Closure compiler is giving me a warning of: "WARNING - Suspicious code. This code lacks side effects, is there a bug?" Pointing specifically to the last "i" in the for loop parens.

If I remove the i, jslint throws a warning, if I leave it, closure throws a warning. There are three of these loops in total, is there a "closure friendly" way to do this?

Answer 1

How 'bout the normal way?

if (arr && arr.length > 0) {
    for (i = arr.length; i > 0; --i) {
        element = arr.pop();
        //rest of code
    }
}

Putting the decrement in the test is just not the normal way to write a for loop.

Or even more normal:

if (arr && arr.length > 0) {
    for (i = arr.length - 1; i >= 0; --i) {
        element = arr.pop();
        //rest of code
    }
}

...but as you're not using i , it doesn't matter much.

Or you could use a while :

if (arr && arr.length > 0) {
    i = arr.length;
    while (i--) {
        element = arr.pop();
        //rest of code
    }
}

Answer 2

For future readers, if you're reducing an array's length, don't use a for loop, use a while :

if (arr) {
    while (arr.length) {
        element = arr.pop();
        ...
    }
}

Answer 3

是的-这样的事情应该可以解决问题：

for (i = arr.length; i > 0; i--) {

Answer 4

使用jshint而不是jslint并关闭警告。