获取接口 object 的属性

Question

In a Typescript project I'm working on I have the following interfaces:

interface Credentials {
    google?: string,
    facebook?: string,
}

export interface Configuration {
    credentials: Credentials;
}

In a different class I am trying to get the value of one of the properties of Credentials based on the given string:

export default class Authorize {

    _config : Configuration;

    constructor(config?: Configuration) {
        this._config = config;
    }

    authorize(provider : string) {
        const test = getProperty(this._config.credentials, provider);
        console.log(test);
    }
}

Where the getProperty is:

export function getProperty<T, K extends keyof T>(obj: T, key: K) {
    console.log(typeof key);
    return obj[key];
}

Unfortunately this is not possible since getProperty gives an error:

TS2345: Argument of type 'string' is not assignable to parameter of type 'keyof Credentials'.

Is there a different way to get the property of the Credentials object by string?

Answer 1

I fixed it by adding [key: string]: any, to the Credentials interface.

So the final interface looks like:

interface Credentials {
    [key: string] : any,
    google?: string,
    facebook?: string,
}