An extensible base model class

base-model.ts

export class BaseModel {
  protected properties: string[];
  protected relationships: string[] = [];

  constructor(data: any, properties: string[], relationships: string[] = []) {
    if (!!data) {
      Object.keys(data).forEach(key => {
        this[key] = data[key];
      });
    }

    this.properties = properties;
    this.relationships = relationships;
  }

  toJson(includeRelations = true): {[key: string]: any} {
    // get own props
    const json = this.properties.reduce((acc, prop) => ({ ...acc, [prop]: this[prop] }), {});
    return {
      ...json,
      ...(includeRelations ? this.relationshipsToJson() : {})
    };
  }

  protected mapPropsToInt(props: string[]): void {
    if (!!props) {
      props.forEach(name => {
        if (this.hasOwnProperty(name)) {
          this[name] = (!!this[name] || this[name] === '0') ? +this[name] : 0;
        }
      });
    }
  }

  protected mapPropToModel(prop: string, Model: any): void {
    if (this.hasOwnProperty(prop)) {
      this[prop] = (!!this[prop]) ? new Model(this[prop]) : undefined;
    }
  }

  private relationshipsToJson(): {[key: string]: any} {
    if (this.relationships.length === 0) {
      return {};
    }

    return this.relationships.reduce((acc, key) => {
      const rel = this[key];
      if (!! rel) {
        acc[key] = Array.isArray(rel) ? rel.map(item => item.toJson()) : rel.toJson();
      }
      return acc;
    }, {});
  }
}