Is there an issue with my approach to using TypeScript generics in classes?


class Some<AttributeType = {
    bar: string
}> {
    foo(attrs: AttributeType) {
        if (attrs.bar) {
            console.log(attrs.bar)
        }
    }
}

Unable to run TypeScript code due to a specific error message:

Property 'bar' does not exist on type 'AttributeType'.

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Answer №1

To enhance your code, try implementing the extends keyword instead of using =:

class Some<AttributeType extends {  bar: string  }>

You can find more information on this topic (here in TypeScript generic constraints document).

When you use the = syntax, you are providing a default generic parameter which limits the flexibility of your class usage like so:

let x: Some;

If you want to avoid this restriction, defining a constraint is necessary for ensuring that your generic type always includes the bar field.

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