Using Angular to declare a variable for reuse within nested HTML elements

Exploring the realm of angular development has sparked my interest, however, I found myself at a roadblock while reading through the documentation. The issue lies in figuring out how to declare a variable that can be reused effectively within nested HTML elements.

To address this challenge, I've implemented a workaround that gets the job done, but it feels like a messy solution. I'm eager to discover the correct approach to handling this situation.

In essence, I have an identifier called 'someProperty' that I wish to utilize in multiple locations within the nested HTML elements. This includes using it as the formControlName and passing it as an argument in function calls. Currently, I've resorted to utilizing *ngFor to define the 'x' variable for this purpose.

<div class="container-row" *ngFor="let x of ['someProperty']">
  <span *ngIf="isReadOnly(x)" class="readonly-indicator"></span>
  <span *ngIf="!isReadOnly(x)" class="writable-indicator"></span>
  <mat-form-field>
    <input matInput type="number" formControlName="{{x}}"
           [readonly]="isReadOnly(x)"
           (change)="onChange($event, x)"
           placeholder="This is some Property!">
    <mat-error *ngIf="!someFormGroup.controls[x].valid">ERROR!</mat-error>
  </mat-form-field>
</div>

Answer №1

It seems like the solution you are looking for is utilizing a FormArray. This allows you to have form controls and retrieve their values as an array. Check out this helpful post for more details.

For additional resources on FormArray usage, take a look at this article and another comprehensive guide.

If this meets your requirements, kindly mark this response as the accepted answer. Thank you!

Answer №2

To ensure a constant value in your component, you can create a readonly variable.

readonly MY_CONSTANT = 'someValue'

Then, you can easily access this constant in your template:

<div class="content-box" *ngFor="let item of [MY_CONSTANT]">

I trust this explanation is helpful for you.

UPDATE:

<div class="content-box" *ngFor="let item of ([MY_CONSTANT] as myTemplateVariable)">
{{ formGroup.controls[myTemplateVariable].value }}
</div>

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