Typescript, block cast type to variable, how?

Question

typescript

Hello, I'm picking typescript and one question doesn't even google: let's say this code:

on(types: string|string[]|Object, fn: Function, context?: Object): Emitter {
        // types can be a view of types/handlers
        if (typeof types == 'object') {
            for (let type in <Object>types) {
                // we don't process space-separated events here for performance;
                // it's a hot path since Layer uses the on(obj) syntax
                this._on(type, types[type], fn);
            }

        }
        // ...
    }

here I cast `types`, otherwise the compiler swears. If you have to use `types` several times in this block, then you will have to cast `Object` each time, which is not convenient, or you can write something like this:
let t = <Object>types;
continue to use `t` instead of `types`. This is already convenient, but at the output a code is generated with an obviously superfluous assignment, somehow it is not beautiful, but I want the resulting code to remain normal.
Is it possible somehow to make it convenient and without govnokoda output?

Answer 1

So you can’t do anything here, because types can be of 3 types and each time you have to cast.