Repository navigation
Property with getter: This condition will always return 'false' #46771
Description
Bug Report
🔎 Search Terms
- getter condition
🕗 Version & Regression Information
- This seems like intended behavior (it is sometimes, but not in this case)
⏯ Playground Link
Playground link with relevant code
💻 Code
class Example {
private get _foo() {
return Math.random() < 0.5 ? "a" : "b";
}
bar() {
if (this._foo === "a") {
console.log("got 'a'");
// this error should not occur:
if (this._foo === "b") {
console.log("lucky case, got 'b' too");
}
}
}
}
class Span {
get end() { return this.start + this.length }
constructor(public start: number, public length: number) {}
}
const span = new Span(4, 2);
if (span.end == 6) {
span.length += 1;
// same here:
if (span.end == 7) {
console.log("worked");
}
}🙁 Actual behavior
An error occured because TypeScript thinks this._foo/span.end doesn't change until that if-check, but in these examples it does.
🙂 Expected behavior
There shouldn't be such checks with getters.
Activity
MartinJohns commentedon Nov 11, 2021
Another duplicate of #9998.
fatcerberus commentedon Nov 11, 2021
For the record: TypeScript makes no distinction between getters and plain properties at the type level.
typescript-bot commentedon Nov 13, 2021
This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.