Wrong autofix in `explicit-length-check`

[andrmoel]

There is a wrong autofix for the explicit-length-check rule.

My code:

if (!foo.length > 0) {
 ...

Code after autofix:

if (foo.length === 0 > 0) {
 ...

Expected replacement

if (foo.length === 0) {
 ...

[dimaMachina]

your code is already invalid

if length = 0 true > 0 if length > 0 false > 0

[andrmoel]

your code is already invalid

if length = 0 true > 0 if length > 0 false > 0

Sorry but I don't get it. My code works as expected. I might give a better example:

    const foo = [];

    if (!foo.length > 0) {
        console.log('foo is empty');
    } else {
        console.log('foo is not empty');
    }

    // Result "foo is empty"

Expected outcome after autofix:

    const foo = [];

    if (foo.length === 0) {
        console.log('foo is empty');
    } else {
        console.log('foo is not empty');
    }

    // Result "foo is empty"

You can add some items to the foo array and you will get the other console log.

[andrmoel]

Ok get it!

!foo.length should be transpilled to foo.length === 0

Make sense. So the > operator is unnecessary.

[fregante]

The autofix is correct, !length produces the same result as length === 0. As mentioned before, your code is wrong; use !foo.length OR foo.length > 0, not both.

[fisker]

Strictly speaking, the auto fix isn't correct,

if (foo.length === 0 > 0) ;

means

if (foo.length === (0 > 0)) ;

not

if ((foo.length === 0) > 0) ;

---

Update: This means the autofix also breaks cases uses operators between ! and ===

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_precedence

Maybe we should keep this open for edge cases.

[fregante]

You're right, I did some tests but did not finish my boolean table

!3 > 0	🔴 false
3 === 0 > 0	🔴 false
!0 > 0	🟢 true
0 === 0 > 0	🔴 false