Exploring a particular code snippet, it defines an object with three methods, each requiring a different number of arguments. The code then dynamically calls one of these methods based on a variable's value using the apply() method along with an args array.
class Obj {
a() {
return 0;
}
b(one: string) {
return 1;
}
c(one: string, two: string) {
return 2;
}
}
const obj = new Obj();
function callMethod(method: keyof Obj, ...args: any[]): void {
obj[method].apply(obj, args) // Errors
}
callMethod('a');
Upon compiling the code, TypeScript raises an error because the args array might be empty when calling the b() and c() methods that expect parameters:
The 'this' context of type '(() => number) | ((one: string) => number) | ((one: string, two: string) => number)' is not assignable to method's 'this' of type '(this: Obj) => number'.
Type '(one: string) => number' is not assignable to type '(this: Obj) => number'.
This scenario showcases a JavaScript issue where method names are called dynamically based on variable values.
How can I inform the type checker that:
- every time method
a()is called,argswill be empty - every time method
b()is called,argswill have one element - every time method
c()is called,argswill have two elements
Alternatively, if there is a better approach to solving this issue, I am open to suggestions!