Extending an External Object with Custom Properties in TypeScript

Question

Extending an External Object with Custom Properties in TypeScript

When working with an external library, I often find myself needing to add new properties to passed-in parameters. Instead of using (<any>conv.data) due to the compiler error Object is of type 'unknown', I'm curious if there's a more effective approach for achieving this.

Any suggestions on how to improve this process?

import { dialogflow, Permission } from 'actions-on-google';

const app = dialogflow({ debug: true });

app.intent('actions_intent_PERMISSION', (conv, _, permissionGranted) => {
  if (!permissionGranted) {
    conv.ask('Bye Bye!')
  } else {
    (<any>conv.data).userName = conv.user.name.display
    conv.ask(`Thanks, ${(<any>conv.data).userName}.`)
  }
})

typescript

Answer 1

Answer №1

It seems like there is type information available for conv, but the data attribute is missing. It's important to define data in some way; if not, it would be best to update the type information to include data. You could consider defining data as any, although specifying its properties (optional ones can be marked as optional) would be more beneficial. Alternatively, you could define it as [key: string]: any, but this may not offer much advantage over just using any.

If there is no type information available for conv, you have the option to define it yourself. Here is an example:

interface Conv {
    ask(msg: string): void;
    data: {[key: string]: any};
    user: {
        name: {
            display: appropriateTypeHere;
       }
    }
}

Answer 2

It seems like there is type information available for conv, but the data attribute is missing. It's important to define data in some way; if not, it would be best to update the type information to include data. You could consider defining data as any, although specifying its properties (optional ones can be marked as optional) would be more beneficial. Alternatively, you could define it as [key: string]: any, but this may not offer much advantage over just using any.

If there is no type information available for conv, you have the option to define it yourself. Here is an example:

interface Conv {
    ask(msg: string): void;
    data: {[key: string]: any};
    user: {
        name: {
            display: appropriateTypeHere;
       }
    }
}

Extending an External Object with Custom Properties in TypeScript

Answer №1

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