Basics of Retrieving Data
Explore the fundamentals of data retrieval in Ionic by understanding asynchronous techniques like Promises and Observables, and mastering operators such as map and filter. This lesson helps you manage data streams, parse remote content, and effectively integrate external data sources into your Ionic applications.
We'll cover the following...
From working with social media APIs and remote database-driven records to handling content stored in external JSON files, most modern apps rely, to some degree, on imported data.
Without this data to drive the content for such apps, even the most polished UI isn’t going to count for much.
Thankfully, as Ionic is built on top of the Angular framework, we can use the built-in HttpClient service to simplify the process of loading, retrieving, and parsing external data for our apps.
Before we do this, though, we need to familiarize ourselves with the following:
- Promises
- Observables
- Maps
- Filters
Promises
A Promise is used to handle asynchronous operations (scripts that do not wait for a certain piece of code to finish executing before moving onto the next line), such as retrieving remote server data or completing an SQLite ...