Typescript : Property does not exist on type 'object'

You probably have allProviders typed as object[] as well. And property country does not exist on object. If you don't care about typing, you can declare both allProviders and countryProviders as Array<any>:

let countryProviders: Array<any>;
let allProviders: Array<any>;

If you do want static type checking. You can create an interface for the structure and use it:

interface Provider {
    region: string,
    country: string,
    locale: string,
    company: string
}

let countryProviders: Array<Provider>;
let allProviders: Array<Provider>;

If your object contains any key/value pairs, you could declare an interface called keyable like :

interface keyable {
    [key: string]: any  
}

then use it as follows :

let countryProviders: keyable[];

or

let countryProviders: Array<keyable>;

For your specific case try to define the key type and use Record utility to define the object :

type ProviderKey="region" | "country" | "locale" | "company"

let countryProviders: Array<Record<ProviderKey,string>>;

Yes the above methods are highly recommended, but if you have no choice and want to continue using "allProviders" as an array of object, then go for this method. This worked for me without creating an interface.

if(providers["country"] === "US") // replacement