type TypeofArray<
    ArrayTypeInstance
> = ArrayTypeInstance extends (infer ElementType)[] ? ElementType : never;

type Property = {
    dataId: number;
    address: string;
    price?: number;
    transactionType: string;
    bedrooms?: number;
    coverImageUrl?: string;
    modifiedWhen: string;
    currentStage?: string;
};

type PropertiesState = {
    searchType: TypeofArray<typeof SEARCH_TYPES>;
    properties: Property[];
    [key: number]: boolean;
};

export class Properties extends Component<{}, PropertiesState> {
    readonly state = {
        searchType: 'buy',
        properties: []
    };
...

<PropertyCard
                    isFavorite={this.state[property.dataId]}
                />

readonly state: PropertiesState = {
    searchType: 'buy',
    properties: []
};