I'm trying to give a dynamically assigned id for a div inside a *ngFor. I would like the divs to be called 'wave1, wave2, wave3' etc.
<li *ngFor="let episode of episodes; let i = index">
<div id="wave{{i}}"></div>
</li>
However, this throws the following error:
ERROR DOMException: Failed to execute 'querySelector' on 'Document': '#wave[object Object]' is not a valid selector.
You can use {{ 'wave' + i }} instead of wave{{i}}. Make it as Angular Experession. This is the full ngFor:
<li *ngFor="let episode of episodes; let i = index">
<div id="{{ 'wave' + i }}"></div>
</li>
It works and creates the div with the correct id
document.getElementById("wave1")
Output will be like this:
<div id="wave1">wave1</div>
but remember your code will start from wave0 as i = index starts from 0.
What you have is correct and should work in angular 4/5. Are you maybe using a really old, pre-release angular 2 version?
Here is a stackblitz with your code and the code below, both working
https://stackblitz.com/edit/angular-khur4v?file=app%2Fapp.component.html
You can also do it that way, which is the preferred way
<li *ngFor="let episode of episodes; let i = index">
<div [attr.id]="'wave' + i">{{episode.name}}</div>
</li>
You don't need to define i
<li *ngFor="let episode of episodes">
<div id="wave{{episode}}">{{episode}}</div>
</li>EDIT: in case episodes is a list of objects
<li *ngFor="let episode of episodes">
<div id="wave{{episodes.indexOf(episode)}}">{{episode.name}}</div>
</li>