Route parameters with useRoute in Vue - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of useRoute in Vue Router?

useRoute is a function that lets you access the current route object inside a Vue component. It helps you read route details like parameters, query strings, and path.

beginner

How do you access a route parameter named id using useRoute?

<p>First, import <code>useRoute</code> from <code>vue-router</code>. Then call it inside your component to get the route object. Access the parameter with <code>route.params.id</code>.</p>

intermediate

Why should you use useRoute instead of this.$route in Vue 3 Composition API?

<p><code>useRoute</code> works with the Composition API and lets you access route info reactively inside setup functions. <code>this.$route</code> is for Options API and class components.</p>

intermediate

What happens if the route parameter changes while the component is active when using useRoute?

The route object from useRoute is reactive. So if the parameter changes, your component can react to the new value automatically.

beginner

Show a simple example of using useRoute to display a route parameter userId in a Vue component.

<pre>import { useRoute } from 'vue-router'
import { computed } from 'vue'

export default {
  setup() {
    const route = useRoute()
    const userId = computed(() => route.params.userId)
    return { userId }
  }
}</pre><p>This displays the current <code>userId</code> from the URL.</p>

What does useRoute return in a Vue component?

A The current route object with parameters and query

B A function to change the route

C The router instance

D A boolean indicating if the route is active

useRoute returns the current route object, which includes params, query, and path info.

How do you import useRoute in a Vue 3 component?

A import { useRoute } from 'vue'

B import { useRoute } from 'vue-router'

C import useRoute from 'vue'

D import { useRoute } from 'vuex'

You import useRoute from the vue-router package.

If your route is defined as /user/:id, how do you get the id inside setup()?

A route.query.id

B route.id

C route.path.id

D route.params.id

Route parameters are accessed via route.params.

What happens if the route parameter changes while using useRoute?

A The route object updates reactively

B The component reloads automatically

C Nothing changes until page refresh

D An error is thrown

The route object from useRoute is reactive and updates automatically.

Which Vue API style is useRoute designed for?

A Template-only API

B Options API

C Composition API

D Class API

useRoute is designed for the Composition API in Vue 3.

Explain how to access and use route parameters inside a Vue 3 component using useRoute.

Think about how to get the current route and read its params reactively.

Describe why useRoute is preferred over this.$route in Vue 3 Composition API.

Consider the differences between Options API and Composition API.

Practice

1. What does the useRoute function in Vue Router allow you to do inside a component?

easy

A. Access the current route's parameters and information

B. Change the URL path programmatically

C. Register a new route dynamically

D. Navigate to a different route without reloading

Solution

1. Step 1: Understand the purpose of useRoute

   useRoute is a Vue Router composable that provides access to the current route object inside a component.

2. Step 2: Identify what can be accessed with useRoute

   It allows reading route parameters, query, name, and path but does not change routes or register them.

3. Final Answer:

   Access the current route's parameters and information -> Option A

4. Quick Check:

   useRoute reads route info = B [OK]

Hint: useRoute reads route info, doesn't change or register routes [OK]

Common Mistakes:

• Thinking useRoute changes routes
• Confusing useRoute with useRouter
• Assuming useRoute registers routes

2. Which of the following is the correct way to import and use useRoute in a Vue 3 component's setup() function?

easy

A. import { useRoute } from 'vue-router'; const route = useRoute(route);

B. import useRoute from 'vue-router'; const route = useRoute();

C. import { useRoute } from 'vue-router'; const route = useRoute();

D. import { useRoute } from 'vue'; const route = useRoute();

Solution

1. Step 1: Check the import source

   useRoute is exported from 'vue-router', so import must be from 'vue-router'.

2. Step 2: Verify usage syntax

   The correct usage is calling useRoute() without arguments to get the current route object.

3. Final Answer:

   import { useRoute } from 'vue-router'; const route = useRoute(); -> Option C

4. Quick Check:

   Correct import and call = D [OK]

Hint: Import from 'vue-router' and call useRoute() with no arguments [OK]

Common Mistakes:

• Importing from 'vue' instead of 'vue-router'
• Calling useRoute with arguments
• Using default import instead of named import

3. Given this Vue 3 component code snippet, what will be logged when the URL is /user/42 and the route is defined as /user/:id?

import { useRoute } from 'vue-router';
import { onMounted } from 'vue';

export default {
  setup() {
    const route = useRoute();
    onMounted(() => {
      console.log(route.params.id);
    });
  }
}

medium

A. null

B. undefined

C. user

D. 42

Solution

1. Step 1: Identify the route parameter

   The route is defined as /user/:id, so id is a parameter expected in route.params.

2. Step 2: Check the URL and logged value

   The URL is /user/42, so route.params.id will be "42". The console logs this value on mount.

3. Final Answer:

   42 -> Option D

4. Quick Check:

   route.params.id = "42" [OK]

Hint: Route param matches URL segment after colon :id [OK]

Common Mistakes:

• Expecting param name instead of value
• Confusing params with query
• Logging before route is ready

4. What is the main issue with this Vue 3 component code that tries to react to route parameter changes?

import { useRoute } from 'vue-router';
import { computed } from 'vue';

export default {
  setup() {
    const route = useRoute();
    const userId = computed(() => route.params.id);
    return { userId };
  }
}

The component does not update userId when the route changes.

medium

A. The route object is not reactive, so computed won't update

B. The computed function is missing a dependency array

C. The useRoute hook must be called inside onMounted

D. The userId should be a ref, not computed

Solution

1. Step 1: Understand reactivity of route

   The route object returned by useRoute() is reactive, but its params property is not deeply reactive by default.

2. Step 2: Why computed does not update

   Because route.params is not reactive, the computed property does not track changes, so userId stays the same.

3. Final Answer:

   The route object is not reactive, so computed won't update -> Option A

4. Quick Check:

   Route params not reactive = A [OK]

Hint: Route params are not deeply reactive; watch route.fullPath instead [OK]

Common Mistakes:

• Assuming route.params is reactive
• Calling useRoute inside lifecycle hooks
• Using ref instead of computed incorrectly

5. You want to create a Vue 3 component that displays the user ID from the route parameter and updates automatically when the route changes. Which approach correctly achieves this?

import { useRoute } from 'vue-router';
import { computed, watch, ref } from 'vue';

export default {
  setup() {
    const route = useRoute();
    // What should userId be?
    const userId = ???
    return { userId };
  }
}

hard

A. computed(() => route.params.id)

B. computed(() => route.params.id) with a watch on route.fullPath to trigger updates

C. computed(() => route.fullPath.split('/')[2])

D. ref(route.params.id) without any watcher

Solution

1. Step 1: Understand reactivity limitations

   Route params are not deeply reactive, so computed(() => route.params.id) alone won't update when params change.

2. Step 2: Use a watch on route.fullPath to trigger updates

   Watching route.fullPath (which is reactive) and recomputing userId ensures updates when the route changes.

3. Final Answer:

   computed(() => route.params.id) with a watch on route.fullPath to trigger updates -> Option B

4. Quick Check:

   Watch route.fullPath for param changes = C [OK]

Hint: Watch route.fullPath to react to param changes in computed [OK]

Common Mistakes:

• Using computed alone without watch
• Parsing fullPath manually without reactivity
• Using ref without updating on route change