Can You Avoid Type Assertion in Go?

How to Avoid Type Assertion in Go

In Go, it's common to work with interfaces to handle types with shared behaviors. However, frequently checking the type of an interface value using type assertions can become tedious. This raises the question:

Is it Possible to Create a Variable with Needed Type Instead of Type Assertion?

For example, consider a function that takes an interface:

func method(data interface{})

To access fields or methods of the concrete type, one would normally use type assertion:

switch data.(type) {
case *Struct1:
    a := data.(*Struct1)
    // ...
case *Struct2:
    a := data.(*Struct2)
    // ...
}

However, Go's static typing system prevents creating a variable with a specific type at runtime.

Alternative Solutions

Abstracting Functionality:

Instead of relying on type assertions, create an interface that defines the required functionality. Then, have the concrete types implement this interface. Assign the interface value to a variable of this type, eliminating the need for type assertions.

Using Reflection:

In cases where abstraction is not possible, reflection can be used to access common fields by their name. While this solution allows for dynamic type handling, it lacks compile-time guarantees and may have performance implications.

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