Are If-instanceof-statements considered harmful in Typescript?

Question

Are If-instanceof-statements considered harmful in Typescript?

   selectAction: (actionEvent) => {
        if (actionEvent instanceof Action1) { 
            // action1 body implementation
        } else if (actionEvent instanceof Action2) {
            // action2 body implementation
        } 
    }

This code snippet is designed to handle different types of actions with unique functionalities. However, relying on if-else conditions for each type of action may not be the most scalable solution. As new actions are added in the future, the code will become increasingly complex and require frequent updates.

Are there any alternative approaches to handling this scenario more efficiently?

javascript typescript if-statement instanceof

Answer 1

Answer №1

Implement the concept of duck typing to eliminate the need for conditional statements. Source

Create a method named selection() within each type instance like Action1 and Action2, and so on, to define the desired functionality you wish to implement. Then simply invoke the selection() method without using any conditions. This way, depending on the type of instance, the corresponding selection() method will be executed.

Answer 2

Implement the concept of duck typing to eliminate the need for conditional statements. Source

Create a method named selection() within each type instance like Action1 and Action2, and so on, to define the desired functionality you wish to implement. Then simply invoke the selection() method without using any conditions. This way, depending on the type of instance, the corresponding selection() method will be executed.

Answer 3

Answer №2

There is no inherent issue with utilizing if/else in TypeScript.

Nevertheless, if you find yourself using instanceof, there is likely a more suitable alternative at your disposal. In such situations, it is highly recommended that the actions themselves should take responsibility for their execution:

selectAction: (actionEvent) => {
    actionEvent.execute();
}

...or

selectAction: (actionEvent) => {
    const action = /*...determine action from actionEvent...*/;
    action.execute();
}

...or a comparable approach (alternatively, you may directly use actionEvent.execute() instead of selectAction).

This concept revolves around polymorphism, wherein distinct objects adhere to the same interface and perform varying operations upon being invoked.

Answer 4

There is no inherent issue with utilizing if/else in TypeScript.

Nevertheless, if you find yourself using instanceof, there is likely a more suitable alternative at your disposal. In such situations, it is highly recommended that the actions themselves should take responsibility for their execution:

selectAction: (actionEvent) => {
    actionEvent.execute();
}

...or

selectAction: (actionEvent) => {
    const action = /*...determine action from actionEvent...*/;
    action.execute();
}

...or a comparable approach (alternatively, you may directly use actionEvent.execute() instead of selectAction).

This concept revolves around polymorphism, wherein distinct objects adhere to the same interface and perform varying operations upon being invoked.

Are If-instanceof-statements considered harmful in Typescript?

Answer №1

Answer №2

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