microsoft / microsoft/TypeScript
Can't use async arrow function in/before super call
@rbuckton ya está trabajando en esto.
Desde el 5/2/2021.
- Lenguaje dominante
- Go
- Estrellas
- 111k
- Forks
- 14.3k
- Merge medio
- 2 d 4 h
- PR fusionados (30 d)
- 132
Descripción
Bug Report
🔎 Search Terms
super async arrow function this
🕗 Version & Regression Information
This only occurs using a target version of ES2016 or lower.
⏯ Playground Link
💻 Code
This works:
class A {
constructor(fn: () => Promise<void>) {
fn();
}
}
class B extends A {
constructor() {
super(async function () {
console.log("Hello");
});
}
}
new B();
This doesn't:
class A {
constructor(fn: () => Promise<void>) {
fn();
}
}
class B extends A {
constructor() {
super(async () => {
console.log("Hello");
});
}
}
new B();
The difference between the examples is the use of an arrow function vs a traditional function.
🙁 Actual behavior
It compiles crashes however at runtime with this error message:
ReferenceError: Must call super constructor in derived class before accessing 'this' or returning from derived constructor
The error lies in the generated __awaiter function trying to access this. The traditional function wraps the __awaiter call (therefore binding its own this) not causing it to fail.
🙂 Expected behavior
Print Hello to the console.
Guía de contribución
Primeros pasos
- Lee el issue completo y luego la guía de contribución del proyecto.
- Comenta en el issue que vas a ocuparte — evita que dos personas hagan lo mismo.
- Haz un fork del repositorio y trabaja en una rama.
- Abre un pull request que haga referencia al número del issue.
Evaluación
Este issue todavía no se ha evaluado.