Defining routes array in Angular - Mini Project: Build & Apply

Defining routes array

📖 Scenario: You are building a simple Angular app that has multiple pages. To navigate between pages, you need to set up routes.

🎯 Goal: Create a routes array that defines paths and their corresponding components for navigation in an Angular app.

📋 What You'll Learn

Create a routes array with exactly three routes

Each route must have a path and a component

Use the exact paths: '', 'about', and 'contact'

Use the exact component names: HomeComponent, AboutComponent, and ContactComponent

💡 Why This Matters

🌍 Real World

Routing is essential in Angular apps to navigate between different pages or views without reloading the page.

💼 Career

Understanding how to define and export routes is a fundamental skill for Angular developers working on single-page applications.

1

Create routes array with home route

Create a constant called routes and assign it an array with one route object. The route object should have path set to an empty string '' and component set to HomeComponent.

Angular

# Your code here

Hint

Remember to use square brackets [] for the array and curly braces {} for the route object.

2

Add about route to routes array

Add a second route object to the routes array. This route should have path set to 'about' and component set to AboutComponent.

Angular

const routes = [
  { path: '', component: HomeComponent },
  // Add about route here
]

Hint

Separate route objects with commas inside the array.

3

Add contact route to routes array

Add a third route object to the routes array. This route should have path set to 'contact' and component set to ContactComponent.

Angular

const routes = [
  { path: '', component: HomeComponent },
  { path: 'about', component: AboutComponent },
  // Add contact route here
]

Hint

Make sure to add a comma after the second route object before adding the third.

4

Export routes array

Add an export statement to export the routes array so it can be used in the Angular module.

Angular

const routes = [
  { path: '', component: HomeComponent },
  { path: 'about', component: AboutComponent },
  { path: 'contact', component: ContactComponent }
];
// Export routes array here

Hint

Use export const to make the routes array available outside this file.

Practice

1. What does the routes array in Angular define?

easy

A. It defines the styles for each component.

B. It lists all services used in the app.

C. It tells Angular which component to show for each URL path.

D. It sets the database connection strings.

Solution

1. Step 1: Understand the purpose of routes array

   The routes array maps URL paths to components so Angular knows what to display.

2. Step 2: Eliminate unrelated options

   Styles, services, and database connections are not handled by routes.

3. Final Answer:

   It tells Angular which component to show for each URL path. -> Option C

4. Quick Check:

   Routes array = component mapping [OK]

Hint: Routes array links URL paths to components [OK]

Common Mistakes:

• Confusing routes with styles or services
• Thinking routes handle backend connections
• Assuming routes define component logic

2. Which of the following is the correct way to define a route for path 'home' with component HomeComponent?

easy

A. { path: 'home', component: HomeComponent }

B. { path: 'home', redirectTo: HomeComponent }

C. { route: 'home', component: HomeComponent }

D. { path: 'home', component: 'HomeComponent' }

Solution

1. Step 1: Check correct property names

   The route object must have path and component properties.

2. Step 2: Verify component value type

   The component value should be the component class, not a string or redirect.

3. Final Answer:

   { path: 'home', component: HomeComponent } -> Option A

4. Quick Check:

   Use path and component keys correctly [OK]

Hint: Use component class, not string or redirectTo for components [OK]

Common Mistakes:

• Using 'route' instead of 'path'
• Setting component as a string
• Using redirectTo instead of component for components

3. Given this routes array:

const routes = [
  { path: '', component: HomeComponent },
  { path: 'about', component: AboutComponent },
  { path: '**', component: NotFoundComponent }
];

What component will Angular show when the URL path is '/contact'?

medium

A. HomeComponent

B. AboutComponent

C. No component, error occurs

D. NotFoundComponent

Solution

1. Step 1: Match URL path to routes

   Path '/contact' does not match '' or 'about'.

2. Step 2: Use wildcard '**' route

   The '**' path catches all unmatched URLs and shows NotFoundComponent.

3. Final Answer:

   NotFoundComponent -> Option D

4. Quick Check:

   Wildcard '**' = NotFoundComponent [OK]

Hint: Unmatched paths go to '**' route component [OK]

Common Mistakes:

• Assuming empty path matches all URLs
• Thinking unmatched paths cause errors
• Confusing wildcard '**' with empty path

4. Identify the error in this routes array:

const routes = [
  { path: '', component: HomeComponent },
  { path: 'profile', redirectTo: 'user' },
  { path: 'user', component: UserComponent }
];

What is wrong with the route for 'profile'?

medium

A. redirectTo should be used with pathMatch property.

B. redirectTo cannot be used in routes array.

C. component is missing for 'profile' route.

D. Path 'user' should be capitalized.

Solution

1. Step 1: Check redirectTo usage

   When using redirectTo, Angular requires a pathMatch property to specify matching strategy.

2. Step 2: Confirm missing pathMatch causes error

   Without pathMatch, Angular cannot decide when to redirect, causing routing errors.

3. Final Answer:

   redirectTo should be used with pathMatch property. -> Option A

4. Quick Check:

   redirectTo needs pathMatch [OK]

Hint: Always add pathMatch with redirectTo routes [OK]

Common Mistakes:

• Omitting pathMatch with redirectTo
• Thinking redirectTo needs component
• Assuming path names must be capitalized

5. You want to define routes so that:
- The home page shows HomeComponent at path ''.
- The about page shows AboutComponent at path 'about'.
- Any unknown path redirects to home.

Which routes array correctly implements this?

hard

A. [
{ path: '', component: HomeComponent },
{ path: 'about', component: AboutComponent },
{ path: '**', redirectTo: '' }
]

B. [
{ path: '', component: HomeComponent },
{ path: 'about', component: AboutComponent },
{ path: '**', redirectTo: '', pathMatch: 'full' }
]

C. [
{ path: '', component: HomeComponent },
{ path: 'about', component: AboutComponent },
{ path: '*', redirectTo: '', pathMatch: 'full' }
]

D. [
{ path: '', component: HomeComponent },
{ path: 'about', component: AboutComponent },
{ path: '**', component: HomeComponent }
]

Solution

1. Step 1: Check wildcard path for unknown URLs

   The wildcard path for unknown URLs is '**', not '*'.

2. Step 2: Confirm redirectTo usage with pathMatch

   Redirect routes must include pathMatch: 'full' to work properly.

3. Step 3: Verify redirect target and components

   Redirecting '**' to '' sends unknown URLs to home page correctly.

4. Final Answer:

   [ { path: '', component: HomeComponent }, { path: 'about', component: AboutComponent }, { path: '**', redirectTo: '', pathMatch: 'full' } ] -> Option B

5. Quick Check:

   Use '**' with redirectTo and pathMatch 'full' [OK]

Hint: Use '**' wildcard with redirectTo and pathMatch 'full' [OK]

Common Mistakes:

• Using '*' instead of '**' for wildcard
• Omitting pathMatch in redirectTo routes
• Using component instead of redirectTo for redirects