Resolver for pre-fetching data in Angular - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a Resolver in Angular?

A Resolver is a special service that fetches data before a route is activated. It helps load data so the component can display it immediately when it appears.

beginner

How does a Resolver improve user experience?

By loading data before the page shows, the user sees content right away without waiting for data to load after the page appears.

intermediate

Which Angular interface must a Resolver implement?

A Resolver must implement the Resolve<T> interface, where T is the type of data it fetches.

intermediate

Where do you configure a Resolver in Angular?

You add the Resolver to the route's configuration in the RouterModule, using the 'resolve' property with a key for the data.

advanced

What happens if a Resolver fails to fetch data?

If a Resolver fails, the route activation can be canceled or redirected. You can handle errors inside the Resolver to manage this gracefully.

What is the main purpose of an Angular Resolver?

A To fetch data before the route activates

B To style components dynamically

C To handle user input events

D To manage component lifecycle hooks

Resolvers fetch data before the route activates so the component has data ready to display.

Which method must be implemented in a Resolver service?

A resolve()

B fetch()

C load()

D activate()

The resolve() method is required by the Resolve interface to fetch data.

Where do you specify a Resolver in Angular routing?

A In the service's providers array

B In the component's decorator

C In the module's imports array

D In the route's 'resolve' property

Resolvers are configured in the route's 'resolve' property to link data fetching with routing.

What type of value does the resolve() method return?

A String only

B Observable or Promise

C Number only

D Void

resolve() returns an Observable or Promise that resolves the data before route activation.

If a Resolver fails, what can Angular do?

A Ignore the error and load the component

B Automatically retry fetching data

C Cancel route activation or redirect

D Reload the entire application

Angular can cancel the route or redirect if the Resolver fails, allowing error handling.

Explain how an Angular Resolver works and why it is useful.

Think about loading data before showing the page.

Describe how to add a Resolver to an Angular route configuration.

Look at the routing module setup.