Microsoft/TypeScript
Auf GitHub ansehenMisleading error message for missing properties in types composed of the intersection of certain multiple unions
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#53.200 geöffnet am 10. März 2023
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Beschreibung
Bug Report
🔎 Search Terms
intersection of union required property error message
🕗 Version & Regression Information
This is the behavior in every version I tried, and I reviewed the FAQ for entries about it
I use the playground and observed the same behavior for versions 4.2 through 4.9
⏯ Playground Link
Playground link with relevant code
💻 Code
type Arg = (
| {
prefLabel?: string;
showPref: false;
}
| {
prefLabel: string;
showPref?: true;
}
)
& (
| { other: false; }
| { other: true; }
);
const fn = (thing: Arg) => {};
fn({ showPref: false }); // <<< error on this line
fn({ showPref: false, other: true }); // <<< this is ok
🙁 Actual behavior
I see an error for fn({ showPref: false });:
Argument of type '{ showPref: false; }' is not assignable to parameter of type 'Arg'.
Type '{ showPref: false; }' is not assignable to type '{ prefLabel: string; showPref?: true | undefined; } & { other: true; }'.
Property 'prefLabel' is missing in type '{ showPref: false; }' but required in type '{ prefLabel: string; showPref?: true | undefined; }'.(2345)
input.tsx(7, 7): 'prefLabel' is declared here.
This is wrong because actually other is missing. The following line does not produce an error
🙂 Expected behavior
I would expect the error message to refer to the missing required property, not to an irrelevant union member