Models for case study on article "Web app architecture based on Redux"

## article-web-app-architecture-based-on-redux-models.ts
class EntrySer {
    constructor(
        public id: string = null,
        public title: string = '',
        public type: string = 'FLICKR',
        public data: string = '',
        public postBy: UserRef = null,
        public dateCreated: string = null) { }

    public static fields: string = `
            id
            title
            type
            data
            postBy { ${ UserRef.fields} }
            dateCreated
    `;
}

class EntryRef {
    constructor(
        public id: string = null) { }

    public static fields: string = `
            id
    `;

    public static resolveRef(ref: EntryRef, entries: Array<EntrySer>) {
        return entries.find(e => e.id === ref.id);
    }
}

class UserRef {
    constructor(
        public id: string) { }

    public static fields: string = `
        id
    `;

    public static resolveRef(ref: UserRef, users: Array<UserSer>) {
        return users.find(u => u.id === ref.id);
    }
}

class AsyncDataSer<T> {
    public error: boolean = false;
    public errorsData?: Array<ServerError> = null;

    constructor(
        public data: T,
        public loading: boolean = false,
        public cursor: any = null) { }

    public static hasData(adata: AsyncDataSer<any>, orError: boolean = false): boolean {
        if (orError)
            return adata.error || (!adata.loading && adata.data != null);

        return !adata.error && !adata.loading && adata.data != null;
    }

    public static errored<T>(errors?: Array<any>, data: T = null): AsyncDataSer<T> {
        const obs: AsyncDataSer<T> = new AsyncDataSer<T>(data);
        obs.error = true;
        if (errors && Array.isArray(errors))
            obs.errorsData = errors.filter((error) => (error.name && error.name === 'ServerError'));
        return obs;
    }
}