Utilizing Angular 4 to dynamically load a recursive template with input values

Currently, I am developing a component that functions similar to a treeview. Below is the template for my tree-view:

<div>{{templateData?.text}}">1</div>
<div class="row" *ngFor="let child of templateData?.children">
    <tree-view [templateData]="child" ></tree-view>
</div>

Within tree-view.component.ts, I have defined templateData as @Input(). Moreover, in app.component.html:

<tree-view [templateData]="templateData"></tree-view>

As for app.component.ts, I retrieve templateData by making an API call:

this.templateService.getTemplateData().subscribe(data => {
    this.templateData = data;
});

However, there is an issue where the tree-view component loads before templateData initializes. How can I adjust the component to reload its content once templateData updates?

angulartypescript

Answer №1

You have shared a snippet of your code, so I will do my best to address your question based on what you've provided. Here are two potential solutions that come to mind:

Option 1 (*ngIf)

To ensure the tree-view Component waits for data initialization before rendering, you can utilize *ngIf.

<tree-view *ngIf="templateData" [templateData]="templateData" ></tree-view>

Option 2 (ngOnChanges)

Another approach is to use ngOnChanges within the tree-view Component's Component Lifecycle Hook to respond to changes in the input data.

ngOnChanges(changes: SimpleChanges) {
    // Execute custom logic only when the "data" property changes
    if (changes['data']) {
       // Custom Logic here
    }
}

In this scenario, data represents your @Input() value.

I also noticed an error in your code:

<div>{{template?.text}}">1</div>

There seems to be an HTML error in this line. You can either remove the quotes or the entire section ">1

<div>{{template?.text}}>1</div> or <div>{{template?.text}}</div>

Lastly, it would be helpful if you could share the complete Tree View Component TS file and the relevant segment of app.component.ts where you initialize the Data.

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