How to detect changes in a list of drop down elements?

Issue

I have a list of users. Each user is a composite object: { id: '123', name: 'Bob', State: 'Colorado' }

I render those users using an *ngFor:

<div *ngFor="let u in users">
    {{ u.name }}
    <select [(ngModel)]="u.state">
       <option *ngFor="let s in states" [value]="s">{{s}}</option>
    </select>
</div>

When select-value changes - I want to save the object over REST API.

I tried adding (change)="changeState(u)", but that does not work, apparently u.state is being updated after my (change) callback is executed.

If I would not have a loop, I would give my dropdown a reference: #state and then use (change)="changeState(u, state.value)"

Is my only option is to use $event.target.value? Or is there a slicker way to do this? This solution also takes away validation.

Is any of the first two solution attempts salvageable?

Solution

You can separate the ngModelChange event from ngModel:

<select [ngModel]="u.state" (ngModelChange)="changeState($event)">
       <option *ngFor="let s in states" [value]="s">{{s}}</option>
</select>

then the new select value will be passed to changeState() directly.

Answered By - Daniel Kucal