Tips for incorporating an optional function argument in JavaScript

Incorporating conditional logic using matchPath from React Router is my current task.

I am in the process of defining a function for this purpose.


        import { matchPath } from "react-router";
        
        export const MyKey = {
            Foo: "foo",
            Bar: "bar",
            Home: "",
        } as const;
        
        export const subPageMatch = (
            key: // the key can be `foo` or `bar`,
            path: string,
        ) => {
            return !!matchPath(path, {
                path: `/${key}/:subPage`,
            });
        };
    

The scenarios I need to validate are:


        http://localhost:3000/foo/sub // should return `true`
        http://localhost:3000/bar/sub // should return `true`
        http://localhost:3000/test/sub // should return `false`
        http://localhost:3000/foo/sub/anothersub // should also return `true`
    

How do I structure this function to have a conditional parameter?

And then how can I utilize it like this:


        const test = subPageMatch(---> here should evaluate to one of the values of the object MyKey, pathname);
    

Thus, the first argument can only be either

"foo" || "bar"
.

Answer №1

To retrieve the values stored in MyKey, you first need to access the keyof property and then use it to extract the value. Once you have the value, you can utilize Exclude to eliminate the option of ''.

For example:

Exclude<typeof MyKey[keyof typeof MyKey], ''>

TS Playground

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