strictPropertyInitialization does not check enum/const computed property names

[peterflynn]

Bug Report

🔎 Search Terms

"no initializer and is not definitely assigned in the constructor", computed property name, const string property name, symbol class field, enum class field

🕗 Version & Regression Information

Seen in: 3.3.3, 3.9.7, and 4.1.3

⏯ Playground Link

Playground link for the code below

💻 Code

const two = "two";

enum OtherProps {
    three = "three",
    four = "four"
}

class Foo {
    // 👍 ERROR: Property 'one' has no initializer and is not definitely assigned in the constructor.
    one: string;

    // 🙁 No error
    [two]: string;

    // 🙁 No error
    [OtherProps.three]: string;
}

🙁 Actual behavior

The "two" and "three" properties are accepted without error, even though they're just as incorrect (never initialized) as "one."

🙂 Expected behavior

The "strictPropertyInitialization" error should trigger for all three cases -- since the property name is statically known at compile time for all three, they're all equally able to be checked.

When computed properties use a more complex expression that can't be resolved at compile time, it's understandable that TypeScript can't reason about it as effectively. But the cases above are statically understood, to the point where you can access them via regular identifiers elsewhere: if you write new Foo().two or .three, its type is string.

It's true that strictPropertyInitialization could give false positive errors by missing places where they are initialized via more dynamic indexing (e.g. foo[getProp()] =""). But isn't that equally true for one (getProp() could return "one")? If we're willing to accept that sort of potential for false-positives for the one case, it should be equally acceptable risk for the other cases as well.

[peterflynn]

Does this have a similar root cause as limitations like #25758?

[MartinJohns]

Duplicate of #36302. Used search terms: strictpropertyinitializatiom computed

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.