Angular2 : render a component without its wrapping tag

I am struggling to find a way to do this. In a parent component, the template describes a table and its thead element, but delegates rendering the tbody to another component, like this:

<table>
  <thead>
    <tr>
      <th>Name</th>
      <th>Time</th>
    </tr>
  </thead>
  <tbody *ngFor="let entry of getEntries()">
    <my-result [entry]="entry"></my-result>
  </tbody>
</table>

Each myResult component renders its own tr tag, basically like so:

<tr>
  <td>{{ entry.name }}</td>
  <td>{{ entry.time }}</td>
</tr>

The reason I'm not putting this directly in the parent component (avoiding the need for a myResult component) is that the myResult component is actually more complicated than shown here, so I want to put its behaviour in a separate component and file.

The resulting DOM looks bad. I believe this is because it is invalid, as tbody can only contain tr elements (see MDN), but my generated (simplified) DOM is :

<table>
  <thead>
    <tr>
      <th>Name</th>
      <th>Time</th>
    </tr>
  </thead>
  <tbody>
    <my-result>
      <tr>
        <td>Bob</td>
        <td>128</td>
      </tr>
    </my-result>
  </tbody>
  <tbody>
    <my-result>
      <tr>
        <td>Lisa</td>
        <td>333</td>
      </tr>
    </my-result>
  </tbody>
</table>

Is there any way we can get the same thing rendered, but without the wrapping <my-result> tag, and while still using a component to be sole responsible for rendering a table row ?

I have looked at ng-content, DynamicComponentLoader, the ViewContainerRef, but they don't seem to provide a solution to this as far as I can see.

Answers:

Answer

You can use attribute selectors

@Component({
  selector: '[myTd]'
  ...
})

and then use it like

<td myTd></td>
Answer

Use this directive on your element

@Directive({
   selector: '[remove-wrapper]'
})
export class RemoveWrapperDirective {
   constructor(private el: ElementRef) {
       const parentElement = el.nativeElement.parentElement;
       const element = el.nativeElement;
       parentElement.removeChild(element);
       parentElement.parentNode.insertBefore(element, parentElement.nextSibling);
       parentElement.parentNode.removeChild(parentElement);
   }
}

Example usage:

<div class="card" remove-wrapper>
   This is my card component
</div>

and in the parent html you call card element as usual, for example:

<div class="cards-container">
   <card></card>
</div>

The output will be:

<div class="cards-container">
   <div class="card" remove-wrapper>
      This is my card component
   </div>
</div>
Answer

You need "ViewContainerRef" and inside my-result component do something like this:

html:

<ng-template #template>
    <tr>
       <td>Lisa</td>
       <td>333</td>
    </tr>
 </ng-template>

ts:

@ViewChild('template') template;


  constructor(
    private viewContainerRef: ViewContainerRef
  ) { }

  ngOnInit() {
    this.viewContainerRef.createEmbeddedView(this.template);
  }
Answer

Attribute selectors are the best way to solve this issue.

So in your case:

<table>
  <thead>
    <tr>
      <th>Name</th>
      <th>Time</th>
    </tr>
  </thead>
  <tbody my-results>
  </tbody>
</table>

my-results ts

import { Component, OnInit } from '@angular/core';

@Component({
  selector: 'my-results, [my-results]',
  templateUrl: './my-results.component.html',
  styleUrls: ['./my-results.component.css']
})
export class MyResultsComponent implements OnInit {

  entries: Array<any> = [
    { name: 'Entry One', time: '10:00'},
    { name: 'Entry Two', time: '10:05 '},
    { name: 'Entry Three', time: '10:10'},
  ];

  constructor() { }

  ngOnInit() {
  }

}

my-results html

  <tr my-result [entry]="entry" *ngFor="let entry of entries"><tr>

my-result ts

import { Component, OnInit, Input } from '@angular/core';

@Component({
  selector: '[my-result]',
  templateUrl: './my-result.component.html',
  styleUrls: ['./my-result.component.css']
})
export class MyResultComponent implements OnInit {

  @Input() entry: any;

  constructor() { }

  ngOnInit() {
  }

}

my-result html

  <td>{{ entry.name }}</td>
  <td>{{ entry.time }}</td>

See working stackblitz: https://stackblitz.com/edit/angular-xbbegx

Answer

you can try use the new css display: contents

here's my toolbar scss:

:host {
  display: contents;
}

:host-context(.is-mobile) .toolbar {
  position: fixed;
  /* Make sure the toolbar will stay on top of the content as it scrolls past. */
  z-index: 2;
}

h1.app-name {
  margin-left: 8px;
}

and the html:

<mat-toolbar color="primary" class="toolbar">
  <button mat-icon-button (click)="toggle.emit()">
    <mat-icon>menu</mat-icon>
  </button>
  <img src="/assets/icons/favicon.png">
  <h1 class="app-name">@robertking Dashboard</h1>
</mat-toolbar>

and in use:

<navigation-toolbar (toggle)="snav.toggle()"></navigation-toolbar>
Answer

Another option nowadays is the ContribNgHostModule made available from the @angular-contrib/common package.

After importing the module you can add host: { ngNoHost: '' } to your @Component decorator and no wrapping element will be rendered.

Tags

Recent Questions

Top Questions

Home Tags Terms of Service Privacy Policy DMCA Contact Us

©2020 All rights reserved.