💅 lint/correctness/noConstantCondition does not consider enums when apply the rule

[jpike88]

💅 lint/correctness/noConstantCondition does not consider enums when apply the rule

[ah-yu]

Enum members can be either constant or computed values.

Typescript docs: https://www.typescriptlang.org/docs/handbook/enums.html#computed-and-constant-members
Example: https://www.typescriptlang.org/play/?#code/KYOwrgtgBAYg9nKBvAUFKBBANGqAhKAXigFkBDAFwAsA6AJzJABM4IAKAShQF8g

[jpike88]

My god... I didn't know that was possible.

It should be noted though that computed values are only allowed in numeric enums. And once computed they are fixed for the duration of runtime. So in that sense they behave as a constant and having a truthy if statement like that is almost always going to be an accident

[ah-yu]

And once computed they are fixed for the duration of runtime

No, they are not fixed.

zheyzhang@HANM18365 react % cat foo.ts 
enum Foo {
    A,
    B = Math.random(),
}
console.log(Foo.B);
zheyzhang@HANM18365 react % deno run foo.ts 
0.2797788528053844
zheyzhang@HANM18365 react % deno run foo.ts
0.15004983018100404
zheyzhang@HANM18365 react % deno run foo.ts
0.8717746009202871
zheyzhang@HANM18365 react % 

[jpike88]

'for the duration of runtime' so in that sense they are fixed and behave like a constant as they are a readonly property.

[ah-yu]

Sorry, I misunderstood.

While the value is determined at runtime, we cannot know it in advance. If the computed value is 0, it will be treated as false in an if statement.

[Conaclos]

This is out of scope of the current rule. This requires type info.