Rule proposal: Collapsible if-statements

[sindresorhus]

The rule should identify nested if-statements that can be combined into one.

Would be useful if the rule could be auto-fixable.

Instead of:

if (foo) {
    if (bar) {
        // ...
    }
}

Prefer:

if (foo && bar) {
    // ...
}

From: typescript-eslint/typescript-eslint#279

[sindresorhus]

Accepted. PR welcome.

[fisker]

Rule name? collapse-if?

[fregante]

This can only work if it’s not followed by else

Can’t be flattened:

if (x) {
  if (y) {}
} else {}

Can be flattened

if (x) {
 
} else if (x) {
  if (y) {}
}

[fisker]

I think this comment make sense, let's name it as no-lonely-if too, hope it will merge to core someday.

[fregante]

Hasn’t eslint stopped adding rules to core?

[fisker]

No, but @sindresorhus made this proposal here. I guess he want have this rule in unicorn first?

[fisker]

Anyway, the rule is ready #936

[fregante]

According to their rule suggestion issue template:

New rules must be related to ECMAScript features added within the last 12 months

But I suppose this rule could still be accepted as a modification of the existing one.

[sindresorhus]

No, but @sindresorhus made this proposal here. I guess he want have this rule in unicorn first?

Yeah, I have given up bothering proposing stuff over at ESLint. The process there is way too slow and they reject almost everything anyway.