RouterLink for navigation in Angular - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What happens when RouterLink is used incorrectly?

Consider this Angular template snippet:

<a routerLink="['/home']">Home</a>

What will be the result when this link is clicked?

Angular

<a routerLink="['/home']">Home</a>

A The app navigates to the '/home' route as expected.

B The app throws a runtime error because routerLink expects a string, not an array.

C The link reloads the entire page instead of navigating within the app.

D Nothing happens because routerLink is not a valid attribute.

💡 Hint

RouterLink can accept both strings and arrays for navigation paths.

In Angular, routerLink can be used with a string or an array of path segments. Using an array like ['/home'] is valid and navigates correctly.

📝 Syntax

intermediate

Which RouterLink syntax correctly navigates to a child route?

You want to navigate to the child route '/products/details'. Which RouterLink syntax is correct?

A <a routerLink="['products/details']">Details</a>

B <a routerLink="'/products/details'">Details</a>

C <a [routerLink]="['/products', 'details']">Details</a>

D <a routerLink="products/details">Details</a>

💡 Hint

RouterLink array syntax splits path segments by commas.

Using an array with separate segments like ['/products', 'details'] correctly navigates to the child route. The string '/products/details' also works but must be quoted properly.

🔧 Debug

advanced

Why does this RouterLink not navigate as expected?

Given this template:

<a [routerLink]="['/dashboard']">Dashboard</a>

Clicking the link does not navigate. What is the likely cause?

Angular

<a [routerLink]="['/dashboard']">Dashboard</a>

A The RouterModule is not imported in the Angular module.

B The routerLink directive requires parentheses, like routerLink().

C The path '/dashboard' is invalid because it lacks a trailing slash.

D The link must use href instead of routerLink for navigation.

💡 Hint

RouterLink needs RouterModule to work properly.

If RouterModule is not imported in the Angular module, routerLink directives won't function and clicking links won't navigate.

❓ state_output

advanced

What is the value of the href attribute rendered by RouterLink?

Given this Angular template:

<a [routerLink]="['/profile', userId]">Profile</a>

and userId = 42, what is the href attribute value in the rendered HTML?

Angular

userId = 42

A "/profile?userId=42"

B "/profile/42"

C "/profile,userId"

D "/profile/"

💡 Hint

RouterLink builds the URL by joining path segments.

RouterLink joins the array segments into a path, so ['/profile', 42] becomes '/profile/42' in the href attribute.

🧠 Conceptual

expert

Which statement about RouterLink and accessibility is true?

Select the correct statement about using RouterLink for navigation and accessibility best practices.

A RouterLink disables default link behavior, so you must add ARIA labels manually.

B RouterLink automatically manages keyboard focus and ARIA roles for all links.

C RouterLink requires adding tabindex="0" to enable keyboard navigation.

D Using RouterLink on <a> tags preserves native keyboard navigation and screen reader support.

💡 Hint

Think about how native tags behave with keyboard and screen readers.

Using RouterLink on tags keeps native link behavior, preserving keyboard navigation and screen reader accessibility without extra attributes.

Practice

1. What is the main purpose of RouterLink in Angular?

easy

A. To fetch data from a server

B. To style buttons with CSS classes

C. To create clickable links that navigate within the app without reloading the page

D. To define routes in the app module

Solution

1. Step 1: Understand RouterLink's role

   RouterLink is used to create links that change the URL and navigate inside the Angular app smoothly.

2. Step 2: Differentiate from other features

   It does not style buttons, fetch data, or define routes; those are separate tasks.

3. Final Answer:

   To create clickable links that navigate within the app without reloading the page -> Option C

4. Quick Check:

   RouterLink = navigation links [OK]

Hint: RouterLink changes URL inside app without page reload [OK]

Common Mistakes:

• Confusing RouterLink with CSS styling
• Thinking RouterLink fetches data
• Mixing RouterLink with route definitions

2. Which of the following is the correct syntax to create a static link to '/home' using RouterLink in a template?

easy

A. Home

B. Home

C. Home

D. Home

Solution

1. Step 1: Identify static RouterLink syntax

   For static paths, use routerLink="/path" without square brackets.

2. Step 2: Check each option

   <a routerLink="['/home']">Home</a> (A) uses array literal as static string, leading to malformed path. <a [routerLink]="/home">Home</a> (B) has invalid binding expression (missing string quotes). <a routerLink=['/home']>Home</a> (C) has wrong brackets syntax without quotes. <a routerLink="/home">Home</a> (D) uses correct static syntax.

3. Final Answer:

   <a routerLink="/home">Home</a> -> Option D

4. Quick Check:

   Static link = no brackets [OK]

Hint: Static links use routerLink without square brackets [OK]

Common Mistakes:

• Using square brackets for static strings unnecessarily
• Missing leading slash in path
• Incorrect bracket placement

3. Given the component template:

<a [routerLink]="['/profile', userId]">Profile</a>

and userId = 42, what URL will the link navigate to when clicked?

medium

A. /profile?userId=42

B. /profile/42

C. /profile/userId

D. /profile

Solution

1. Step 1: Understand array syntax in RouterLink

   Using [routerLink]="['/profile', userId]" creates a URL by joining segments, so it appends userId as a path segment.

2. Step 2: Substitute userId value

   With userId = 42, the URL becomes /profile/42.

3. Final Answer:

   /profile/42 -> Option B

4. Quick Check:

   Array routerLink joins segments with slashes [OK]

Hint: Array syntax adds path segments separated by slashes [OK]

Common Mistakes:

• Thinking it adds query parameters instead of path segments
• Using string interpolation inside array incorrectly
• Ignoring dynamic value substitution

4. Identify the error in this RouterLink usage:

<a [routerLink]="'/dashboard'">Dashboard</a>

medium

A. The binding brackets should be removed for static paths

B. RouterLink cannot be used on <a> tags

C. The path string should not be in quotes inside the binding brackets

D. Missing parentheses around the path

Solution

1. Step 1: Analyze binding syntax

   Using square brackets means Angular expects an expression. Here, the expression is a string literal with quotes, which is valid but unnecessary for static paths.

2. Step 2: Correct usage for static paths

   For static paths, remove square brackets and quotes: routerLink="/dashboard".

3. Final Answer:

   The binding brackets should be removed for static paths -> Option A

4. Quick Check:

   Static path = no brackets [OK]

Hint: Remove brackets for static string paths [OK]

Common Mistakes:

• Using quotes inside binding brackets unnecessarily
• Thinking RouterLink can't be on anchor tags
• Adding parentheses around path

5. You want to create a navigation link that goes to a user detail page with a dynamic user ID, but only if the ID is valid (non-null). Which is the best way to use RouterLink in the template to handle this condition?

hard

A. User Details

B. User Details

C. User Details

D. User Details

Solution

1. Step 1: Understand conditional RouterLink binding

   <a [routerLink]="userId ? ['/user', userId] : ['/user']">User Details</a> uses a ternary operator inside the binding to choose the path based on userId validity, which is clean and safe.

2. Step 2: Evaluate other options

   <a *ngIf="userId" [routerLink]="['/user', userId]">User Details</a> hides the link if userId is falsy, which may be okay but removes the link entirely. <a [routerLink]="['/user', userId || 'default']">User Details</a> uses a fallback string which might not be desired. <a [routerLink]="/user/{{userId}}">User Details</a> uses interpolation inside the binding expression, which is invalid template syntax.

3. Final Answer:

   <a [routerLink]="userId ? ['/user', userId] : ['/user']">User Details</a> -> Option A

4. Quick Check:

   Use ternary inside binding for conditional paths [OK]

Hint: Use ternary operator inside [routerLink] for conditions [OK]

Common Mistakes:

• Using interpolation inside routerLink attribute
• Hiding link instead of changing path
• Using fallback strings that may confuse routing