How to use ngSwitch with *ngFor in Angular 6

Question

I have a Map as follows with dynamic keys and values

public featureData = new Map<string, string>();

Key value pairs will be as follows (other dynamic values may present)

[
  {"name" : "Bangalore"},
  {"type" : "city"},
  {"lat" : "12.9716"},
  {"lon" : "77.5946"}
]

To display this data in HTML, I used the following code

<div class="modal-body">
 <div class="form-group">
  <h4>
   <ol>
    <li *ngFor="let feature of this.featureData | keyvalue"> {{ feature.key }} : <input type="text" class="custom-field form-control form-control-sm form-control form-control-sm-sm"  (change)="updateAnyHashMap(this.featureData, feature.key, $event.target.value)" autocomplete="off" value="{{ feature.value }}"> </li>
   </ol>
  </h4>
 </div>
</div>

And the above code gives me an output as follows

But I need to disable the fields lat and lon using ngSwitch. So that I can get an output as follows

Answer 1

Finally I could find a solution after repeated reading the Angular Documents.

The following code solved my issue :

<ul *ngFor="let feature of this.featureData | keyvalue" [ngSwitch]="feature.key">
  <li *ngSwitchCase="'lat'"> {{ feature.key }} : <input type="text" class="custom-field form-control form-control-sm form-control form-control-sm-sm" value="{{ feature.value }}" disabled>
  </li>

  <li *ngSwitchCase="'lon'"> {{ feature.key }} : <input type="text" class="custom-field form-control form-control-sm form-control form-control-sm-sm" value="{{ feature.value }}" disabled>
  </li>

  <li *ngSwitchCase="'data'"> {{ feature.key }} : <input type="text" class="custom-field form-control form-control-sm form-control form-control-sm-sm" value="{{ feature.value }}" disabled>
  </li>

  <li *ngSwitchDefault> {{ feature.key }} : <input type="text" class="custom-field form-control form-control-sm form-control form-control-sm-sm" (change)="updateAnyHashMap(this.featureData, feature.key, $event.target.value)" autocomplete="off" value="{{ feature.value }}">
  </li>
</ul>

I have used the <ul> tag for looping the data within my Map. That is, featureData. The looped data has been passed to the Switch. As I have to use disabled for known keys lat, lon and data, I kept them in cases and left all others in Default Case.

The (change) function at Default Case was called for my particular usecase and is not related to this question.

Answer 2

I don't understand why do you want to use ngSwitch when you can do it using disabled attribute. I don't think you can use ngSwitch is this case

As we don't have anything to compare with, I am directly comparing with key values

Change your input as

<input type="text" class="custom-field form-control form-control-sm form-control form-control-sm-sm"  (change)="updateAnyHashMap(this.featureData, feature.key, $event.target.value)" autocomplete="off" value="{{ feature.value }}" [disabled]="feature.key === 'lat' || feature.key === 'lon'">

Long story short, I have added following attribute

[disabled]="feature.key === 'lat' || feature.key === 'lon'"