When the JavaScript compiler generates code, the type system is completely removed. There won't be any trace of T at runtime - you need to provide an actual string value to the get() method.
To achieve intelligent typing, create a mapping from entity names passed to doRequest() to their corresponding entity types. Here's an example:
interface EntityMap {
JobView: JobView;
OtherEntity: OtherEntity;
EtCetera: EtCetera;
}
At runtime, there are no instances of type EntityMap; it acts as a helper type for the compiler to understand the relationship between entity names (e.g., "JobView") and their types (e.g., JobView). Interfaces excel in mapping names to types, hence our usage of them.
Your get() method could look like this:
public get<K extends keyof EntityMap>(entityName: K) {
const response = super.doRequest("/api/fetch/" + entityName + "/123");
return response as EntityMap[K];
}
This method requires passing an entityName parameter with a generic type K, which must match one of the keys in EntityMap - namely "JobView", "OtherEntity", or "EtCetera". At runtime, the value of entityName is used to invoke doRequest(), and the response is then returned as type EntityMap[K], where we look up the property named K in EntityMap.
You can utilize it like this:
const r = new RequestyThing();
const jv = r.get("JobView");
// const jv: JobView
Calling r.get("JobView") will prompt the compiler to return a value of type JobView.
I hope this explanation proves helpful. Best of luck!
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