Typescript Duplicate Function Implementation

Question

I have defined the following two function signatures in the same Typescript class, i.e.,

public emit<T1>(event: string, arg1: T1): void {} 

and

public emit<T1,T2>(event: string, arg1: T1, arg2: T2): void {} 

However when transpiling the typescript I get the following error

error TS2393: Duplicate function implementation. 

I thought you could overload functions in typescript providing the number of parameters in the function signature were different. Given that the above signatures have 2 and 3 parameters respectively, why am I getting this transpilation error?

Answer 1

I'm assuming your code looks like this:

public emit<T1>(event: string, arg1: T1): void {} public emit<T1,T2>(event: string, arg1: T1, arg2: T2): void {} public emit(event: string, ...args: any[]): void {     // actual implementation here } 

The problem is that you have {} after the first 2 lines. This actually defines an empty implementation of a function, i.e. something like:

function empty() {} 

You only want to define a type for the function, not an implementation. So replace the empty blocks with just a semi-colon:

public emit<T1>(event: string, arg1: T1): void; public emit<T1,T2>(event: string, arg1: T1, arg2: T2): void; public emit(event: string, ...args: any[]): void {     // actual implementation here } 

Answer 2

export {} 

Just add this line at the top of the typescript file