You can experiment with the given code snippet at the online playground to confirm it.
Consider this code:
class Alpha {
private beta;
constructor(b: Beta) {
this.beta = b;
}
doSomething() {
this.beta.doesNotExist();
}
}
class Beta {
}
I was expecting the compiler error
Property 'doesNotExist' does not exist on type 'Beta'.However, you only receive that error if you specify the type for beta like this:
private beta:Beta;
I assumed TypeScript would infer types for parameter assignments. For instance, the parameter b is of type Beta. You can verify this by adding the following in the constructor:
const test:string = beta;
Upon doing so, you will encounter an error message stating
Type 'Beta' is not assignable to type 'string'.Hence, my query is, why isn't private beta automatically assigned the type of beta?
Or is this a lesson I need to learn and consistently specify types for all private constructor members?