Generated api class is hard to spy on

[Sczlog]

Current

In sta, generated Api class is using arrow function when compile to js, the code will be like this which has an empty prototype, will unable to modify prototype of Api class for testing or monkey patching.

For example, i am writing unit testing, I am not able to use jest.spyOn(api.prototype,'someApi') as it will throw no property on prototype, but have to mock import to replace entire class import like

const spy = jest.fn()
jest.mock('../path/to/sta',()=>{
    return {
        api: function(){
              return {
                  someApi: spy
              }
        }
    }
})

Expected

Using function expression in class, for example compiled to which have a modifiable prototype