Mixed operators with same precedence

The ESLint rule no-mixed-operators is great for making things like

var foo = a && b < 0 || c > 0 || d + 1 === 0;
var bar = a && b || c;

clearer by adding parentheses (rather than having people remember the precedence of && and ||. That said, I’m unconvinced that

var foo = a + b - c

is clearer with parentheses, that is according to this style guide you’d need to write this as

var foo = (a + b) - c

The no-mixed-operators rule has an option for this, allowSamePrecedence and the default is true meaning that var foo = a + b - c is valid code (which I think makes a lot more sense). Is there any reason for having this set to false?

[aboyton]

Thanks for the quick reply.

Actually || and && do have different precedence (see MDN operator precedence or Microsoft operator precedence). As an example true || true && false is true as && has a higher precedence than ||.

Because of this (with "allowSamePrecedence": true) the following are lint errors:

var foo = a || b && c;
var foo = a + b * c;

but these are fine

var foo = a || (b && c);
var foo = a + (b * c);
var foo = a + b - c;

I personally don’t mind which way you go for a + b * c or a + (b * c) (I never get confused here but I get how some people do) but it would be nice to make a + b - c valid code.

[ljharb]

The next (semver-major) release will include it, when we’re ready to release it.