The `no-magic-numbers` rule should ignore indexOf === -1

What version are you using? 2.6.0

What did you do?

/*eslint no-magic-numbers: ["error"]*/

var data = ['foo', 'bar', 'baz'];
var key = 'bar';
var hasKey = data.indexOf(key) !== -1;

What happened? error No magic number: -1 no-magic-numbers

What did you expect to happen? Consider indexOf(something) === -1; as ok, because it’s a common pattern for checking whether something is in array.

[michaelficarra]

@d4rkr00t Instead of whitelisting -1 everywhere, you might want to define a constant const INDEXOF_NOT_FOUND = -1; and compare against that.

[lo1tuma]

I don’t think a commonly used pattern makes the number less magic. The meaning of this number is still implicit.