#angulartutorial

Today, in this tutorial, we will learn the implementation of Route Resolvers in Angular.

What is Angular Resolver?

Angular Resolver is used for pre-fetching some of the data when the user is navigating from one route to another. It can be defined as a smooth approach for enhancing user experience by loading data before the user navigates to a particular component.

Let’s see what the difference is in the routing flow if we implement resolvers.

General Routing Flow v/s Angular Resolver Routing Flow

This section might help you to differentiate between the routing flow with or without resolvers.

Steps 2,3 and 4 are done with the help of resolvers.

So we can conclude that resolver is an intermediate code that is executed between clicking the link and loading the component.

Why Choose Angular Resolvers?

Angular Resolvers let the application fetch remote data from the server before the activatedRoute of the next component is activated. We don’t require a spinner until the data is fetched because we won’t be able to navigate to the next component unless the server data is retrieved.

To understand it better, let’s take one scenario- we want to display the array items in a component received in an unordered list or table. For that, suppose we have *ngIf=”some condition” and our business logic depends upon the length of an array, which will be altered once the API call is successful.

We might face an issue in such a case as the component will be ready before receiving the data (the array item isn’t yet with us). Here comes Route Resolver to rescue. We can use Angular’s Route Resolver class for fetching the data before your component is loaded. And then, the conditional statements can work smoothly with the Resolver.

Resolve Interface