angular material table loop through item array

Question

I try to print in Mat-table my Data.

I'm very close but I'm not able to complete my front end.

My data are :

0: {Group: 1, Rules: Array(1), Title: "NAME"}
1: {Group: 2, Rules: Array(2), Title: "TERRITORY"}

And the array for Group 1 have rules like this (and so on for Group 2):
0: {Date: "1990-01-01", NewRules: 0, Rules: "Ligue Name", Id: 1}
1: {Date: "1990-01-01", NewRules: 1, Rules: "Other rules", Id: 2}

here's the .html code:

<mat-card-content>
  <table mat-table [dataSource]="rules$ | async" class="mat-elevation-z8">

    <!-- DateModifier Column -->
    <ng-container matColumnDef="Date">
      <th mat-header-cell *matHeaderCellDef>Date</th>
      <td mat-cell *matCellDef="let element">
        {{ element.Reules[0].Date }}
      </td>
    </ng-container>

    <!-- Reglement Column -->
    <ng-container matColumnDef="Rules">
      <th mat-header-cell *matHeaderCellDef>Rule</th>
      <td mat-cell *matCellDef="let element">
        {{ element.Rules[0].Rules }}
      </td>
    </ng-container>

  <tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
  <tr mat-row *matRowDef="let row; columns: displayedColumns"></tr>
 </table>
</mat-card-content>

What I've got it's ok If I specify : element.Rules[0].Rules

But I want to loop through each item of the array.

Giving something

Date       Rules

1990/1/1  Ligue Name

1990/1/1  Other Rules

Also if you can give me this hint too. How Can I print for each Group the title before all the rules ?

Group : NAME

Date       Rules

1990/1/1  Ligue Name

1990/1/1  Other Rules

Group: TERRITORY
 etc....

file .ts:

import { Component, OnInit, Input } from "@angular/core";
import { Reglements } from "../models/models";
import { MatDialog } from "@angular/material";
import { FirebaseService } from "../service/firebase.service";
import { Observable } from "rxjs";

@Component({
  selector: "app-reglements",
  templateUrl: "./reglements.component.html",
  styleUrls: ["./reglements.component.css"]
})
export class ReglementsComponent implements OnInit {
  displayedColumns: string[] = ["Date", "Rules"];

  @Input()
  // public boardDirection: AngularFireList<Direction[]>;
  public reglements$: Observable<Reglements[]>;

  constructor(
    private dialog: MatDialog,
    private firebaseService: FirebaseService
  ) {
    this.reglements$ = firebaseService.loadAllRules();
    this.reglements$.forEach(element => {
      console.log("eleem", element);
    });
  }

  ngOnInit() {}
}

Thanks

can you post the datasource object also. it will help to understand more clearly — Zulqarnain Jalil
– Zulqarnain Jalil, Commented Jan 31, 2020 at 20:25
I add the .ts file in the code. The datasource is in a firebase. I give you the way it is build: Group: number , Rules: string[], title: string. And the Rules has : Date: string , NewRules: number, Rules: string, Id: number — baronming
– baronming, Commented Jan 31, 2020 at 20:48
I was asking about exact data that you are using for material table. i want to see the value for rules$ variable — Zulqarnain Jalil
– Zulqarnain Jalil, Commented Jan 31, 2020 at 20:50
like I said : the Rules has : Date: string , NewRules: number, Rules: string, Id: number .... Or in data: {Date: "1990-01-01", NewRules: 0, Rules: "Ligue Name", Id: 1} .Did I understand correctly your request :) — baronming
– baronming, Commented Jan 31, 2020 at 20:54

Eranki · Accepted Answer · 2020-02-01 06:28:31Z

6

What I understood in your question is that you have a dictionary of group, rules and title. Among them, rules is a array of dictionaries and you want to loop through that dictionary and print it in table. So, this is how your datasource looks like:

dataSource = [
               {group: 1, rules: [{'date': '2019-1-31', 'rules': 'Some Rule', id: 1}, {'date': '2019-1-27', 'rules': 'Some Rule', id: 2}], title: 'name'},
               {group: 2, rules: [{'date': '2019-1-31', 'rules': 'Some Rule', id: 1}, {'date': '2019-1-27', 'rules': 'Some Rule', id: 2}], title: 'TERRITORY'}
             ]

After modifying your code:

 <table mat-table [dataSource]="dataSource">
     <ng-container matColumnDef="yourColName">
       <th mat-header-cell *matHeaderCellDef>Group</th>
       <td mat-cell *matCellDef="let element">
           {{element.group}}
       </td>
     </ng-container>
     <ng-container matColumnDef="yourColName">
       <th mat-header-cell *matHeaderCellDef>Rules Array Object</th>
       <td mat-cell *matCellDef="let element">
          <!--THIS IS WHERE YOU ARE ITERATING THROUGH ARRAY OF RULES OBJECT-->
           <ng-container *ngFor="let rule of element.rules">
               {{ rule.date}}, {{rule.rules}}, {{rule.id}}
           </ng-container>
       </td>
     </ng-container>
 </table>

answered Feb 1, 2020 at 6:28

Eranki

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1 Comment

Bitly Over a year ago

You get all the upvotes my friend <3 This answer helped me big time. God Bless

Community · Accepted Answer · 2020-06-20 09:12:55Z

3

If you want to loop through each Rule in given data you can use nested table. I have created some code for nested table using angular material click here

edited Jun 20, 2020 at 9:12

CommunityBot

11 silver badge

answered Jan 31, 2020 at 22:58

Zulqarnain Jalil

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5 Comments

baronming Over a year ago

Great, that's close of what I want. Is it possible to extract the tile to have 1 line with the title only, and under the title add the table rules ? And so on ? very close of what I'm looking for

baronming Over a year ago

Well maybe your Part 2 seems to be what I'm looking for. Let me dig and I'll comeback. thanks

baronming Over a year ago

Ok Part 2 is very close of what I'm looking for. The last problem is that GROUP appear on the same line of the table instead to be like a title. How I can add a line feed after the group section to put the table under ? (I try to add a <br> ) and it doesn't work.

baronming Over a year ago

Your code is working. So I create a StackBlitz with my code to try it... and it works too (The Title is above the rules table). The problem when I launch it with NPM Start in my localhost, the title appear as a column left beside the rules table. And the code that I try on Stackblitz is the same. The difference is I get my data from Firebase. So I change it to use the DataSource in the code... Same problem. Title appear as a column on my localhost, but is OK in the StackBlitz... very curious. But thanks you respond for what I was looking for. Now I need to find Why I have this problem.

user5871859 Over a year ago

What about looping through column names that can be retrieved by capitalizing the first letters of each column field?

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