Display fresh information that has been fetched via an HTTP request in Angular

Recently, I encountered an issue where data from a nested array in a data response was not displaying properly in my component's view. Despite successfully pushing the data into the object programmatically and confirming that the for loop added the items to the existing array during the 'OnInit' lifecycle hook, the table in the view remained empty.

 ngOnInit(): void {
    this._data.getContacts().subscribe(data => this.addAsyncData(data));
  }

  addAsyncData(result){
    for(let i =0; i < result.length; i++) {
      this.people.push(result[i]);
  }
}

This unexpected behavior led me to suspect that the issue might be related to lifecycle hooks.

Answer №1

Without seeing more of your code, it's difficult to say for certain, but it's possible that the changes you've made are not showing up in your template because they're not triggering the necessary change detection.

In Angular, the change detector looks for changes in object references when detecting updates. Simply adding elements to an array may not be enough to trigger this detection; instead, you may need to create a new array altogether.

To ensure proper change detection, consider using the following approach:

addNewData(data){
    this.people = [...this.people, ...data];
}

This method creates a new array with both the existing and new data, effectively updating the reference and triggering the change detection mechanism.

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