CODEWITHSUNDEEP
angulartypescriptrxjs
Madhan
Madhan

Reputation: 5818

Angular filter Observable array

I have an Observable array and I want to filter/find the Project by name. When I try to use the filter option it is saying

enter image description here

ProjectService.ts

import { Injectable } from '@angular/core';
import { Project } from "../classes/project";
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/of';

import { Http } from '@angular/http';


@Injectable()
export class ProjectService {

  private projects: Observable<Project[]>;

  constructor(private http: Http) {
    this.loadFromServer();
  }

  getProjects(): Observable<Project[]> {
    return this.projects;
  }

  private loadFromServer() {
    this.projects = this.http.get('/api/projects').map(res => res.json());
  }

  getProjectByName(name: String) {
    return this.projects.filter(proj => proj.name === name);
  }


}

Project Class

export class Project {
    public name: String;
    public miniDesc: String;
    public description: String;
    public category: String[];
    public images: any[];
}

Upvotes: 47

Views: 105666

Answers (2)

Amol Bhor
Amol Bhor

Reputation: 2522

In your Service you can define <any> type or Project[] type to return the response value and same could be continue with filter. e.g. <any>res.json() or <Project[]>res.json()

and also update your class as suggested by @Sajeetharan

ProjectService.ts

import { Injectable } from '@angular/core';
import { Project } from "../classes/project";
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/of';

import { Http } from '@angular/http';


@Injectable()
export class ProjectService {

  private projects: Observable<Project[]>;

  constructor(private http: Http) {
    this.loadFromServer();
  }

  getProjects(): Observable<Project[]> {
    return this.projects;
  }

  private  loadFromServer(): Observable<any> {
    this.projects = this.http.get('/api/projects').map((res: Response)=> <any>res.json());
  }

  getProjectByName(name: string) {
    return this.projects.filter(proj => proj.name === name);
  }   
}

*always write your filters, conditions or manipulation in component not in services.

Upvotes: -1

Tiep Phan
Tiep Phan

Reputation: 12596

it should be:

getProjectByName(name: String) {
  return this.projects
    .map(projects => projects.filter(proj => proj.name === name));
}

you misunderstood about filter operator. The operator using to filter data return from stream. Your stream return array of object, so you need filter array to get you needed value.

The solution above will return an array after filtered, if you wanna get only one value, using following solution

getProjectByName(name: String) {
  return this.projects
    .map(projects => {
      let fl = projects.filter(proj => proj.name === name);
      return (fl.length > 0) ? fl[0] : null;
    });
}

Upvotes: 75

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