Nested routes and child views in Vue - Step-by-Step Execution

Concept Flow - Nested routes and child views

Start at root route

↓

Match parent route

↓

Render parent component

↓

Check for child route

Yes↓

Render child component inside parent

↓

Display combined view

↓

User navigates to another nested route

↓

Repeat child route matching and rendering

The router matches the parent route first, renders its component, then checks for child routes to render inside the parent, showing nested views.

Execution Sample

Vue

const routes = [
  { path: '/parent', component: ParentView, children: [
    { path: 'child', component: ChildView }
  ]}
];

Defines a parent route with a nested child route that renders inside the parent's view.

Execution Table

Step	URL Path	Route Matched	Component Rendered	View Update
1	/parent	Parent route	ParentView	ParentView displayed, child slot empty
2	/parent/child	Parent + Child routes	ParentView + ChildView	ParentView displayed with ChildView inside
3	/parent/child	No further child	No new component	View stable with Parent + Child
4	/parent	Parent route	ParentView	ChildView removed, only ParentView shown

💡 Navigation ends when no more child routes match or user stops navigating.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 4
currentPath	""	"/parent"	"/parent/child"	"/parent"
matchedRoutes	[]	[Parent]	[Parent, Child]	[Parent]
renderedComponents	[]	[ParentView]	[ParentView, ChildView]	[ParentView]

Key Moments - 2 Insights

Why does the child component render inside the parent component?

Because the parent component includes a <router-view> placeholder where the child component is inserted, as shown in execution_table step 2.

What happens if the URL matches only the parent route?

Only the parent component renders without any child, as seen in execution_table step 1 and 4.

Visual Quiz - 3 Questions

Look at the execution table, what components are rendered at step 2?

A ParentView and ChildView

B Only ParentView

C Only ChildView

D No components rendered

💡 Hint

Check the 'Component Rendered' column at step 2 in the execution_table.

At which step does the child component get removed from the view?

A Step 1

B Step 2

C Step 4

D Step 3

💡 Hint

Look at the 'View Update' column where ChildView is removed.

If a new child route is added under the parent, how would the 'matchedRoutes' variable change?

A It would only include the new child route

B It would include Parent and the new child route when matched

C It would only include the Parent route

D It would be empty

💡 Hint

Refer to the 'matchedRoutes' changes in variable_tracker after step 2.

Concept Snapshot

Nested routes let you show child views inside parent views.
Define children in the parent route's children array.
Parent component must have <router-view> to display children.
URL matches parent first, then child routes.
Child components render inside parent's <router-view>.
Navigating changes matched routes and rendered components.

Full Transcript

Nested routes in Vue Router work by matching the parent route first and rendering its component. Then the router checks if the URL matches any child routes defined inside the parent's children array. If a child route matches, its component renders inside the parent's <router-view> placeholder. This creates a nested view structure where the parent stays visible and the child content changes inside it. For example, navigating to '/parent' renders only the ParentView component. Navigating to '/parent/child' renders ParentView with ChildView inside it. If the user goes back to '/parent', the child component is removed. The variables currentPath, matchedRoutes, and renderedComponents track the current URL, which routes matched, and which components are shown. This helps understand how nested routes update the view step-by-step.

Practice

1. What is the main purpose of nested routes in Vue Router?

easy

A. To load multiple Vue apps on the same page

B. To display child views inside a parent view using <router-view />

C. To create routes without components

D. To disable navigation guards

Solution

1. Step 1: Understand nested routes concept

   Nested routes allow smaller views (child views) to be shown inside bigger views (parent views).

2. Step 2: Identify how child views are displayed

   Child views appear inside the parent component where <router-view /> is placed.

3. Final Answer:

   To display child views inside a parent view using <router-view /> -> Option B

4. Quick Check:

   Nested routes = child views inside parent with <router-view /> [OK]

Hint: Nested routes show child views inside parents with [OK]

Common Mistakes:

• Thinking nested routes load separate apps
• Believing nested routes don't need
• Confusing nested routes with route guards

2. Which of the following is the correct way to define a child route inside a parent route in Vue Router?

easy

A. { path: '/parent', component: Parent, children: [{ path: 'child', component: Child }] }

B. { path: '/parent/child', component: Child }

C. { path: '/parent', component: Parent, child: [{ path: 'child', component: Child }] }

D. { path: '/parent', component: Parent, children: { path: 'child', component: Child } }

Solution

1. Step 1: Recall Vue Router child route syntax

   Child routes go inside a children array property of the parent route object.

2. Step 2: Check each option's structure

   { path: '/parent', component: Parent, children: [{ path: 'child', component: Child }] } correctly uses children: [{ path: 'child', component: Child }]. Options C and D use wrong keys or types. { path: '/parent/child', component: Child } defines a separate route, not nested.

3. Final Answer:

   { path: '/parent', component: Parent, children: [{ path: 'child', component: Child }] } -> Option A

4. Quick Check:

   Child routes = inside children array [OK]

Hint: Child routes go inside a children array in parent route [OK]

Common Mistakes:

• Using 'child' instead of 'children' key
• Defining child routes outside parent route
• Using object instead of array for children

3. Given this route config and components, what will be rendered when navigating to /dashboard/settings?

const routes = [
  { path: '/dashboard', component: Dashboard, children: [
    { path: 'settings', component: Settings }
  ]}
];

// Dashboard.vue template:
// 
Dashboard

// Settings.vue template:
// 
Settings Page

medium

A. Nothing renders due to missing

B. Settings Page

C. DashboardSettings Page

D. Dashboard

Solution

1. Step 1: Understand nested route rendering

   When visiting '/dashboard/settings', Vue renders Dashboard component first, then inside its <router-view /> renders Settings component.

2. Step 2: Combine rendered HTML from both components

   Dashboard shows <h1>Dashboard</h1> and Settings shows <h2>Settings Page</h2>. Both appear together.

3. Final Answer:

   <h1>Dashboard</h1><h2>Settings Page</h2> -> Option C

4. Quick Check:

   Nested route renders parent + child views [OK]

Hint: Nested routes render parent plus child inside [OK]

Common Mistakes:

• Expecting only child component to render
• Forgetting in parent
• Confusing full path with child path

4. What is wrong with this route configuration if child views do not appear?

const routes = [
  { path: '/profile', component: Profile, children: [
    { path: 'edit', component: EditProfile }
  ]}
];

// Profile.vue template:
// 
Profile Page

medium

A. Profile.vue is missing to display child routes

B. Child route path should start with '/'

C. Children array should be outside the parent route object

D. EditProfile component must be imported inside Profile.vue

Solution

1. Step 1: Check how child routes display

   Child routes render inside the parent's <router-view />. Without it, child views won't show.

2. Step 2: Inspect Profile.vue template

   Profile.vue only has <h1>Profile Page</h1> and no <router-view />, so child routes can't render.

3. Final Answer:

   Profile.vue is missing <router-view /> to display child routes -> Option A

4. Quick Check:

   Missing <router-view /> = no child views [OK]

Hint: Parent needs to show child routes [OK]

Common Mistakes:

• Adding '/' at start of child path incorrectly
• Placing children outside parent route object
• Assuming child component imports affect rendering

5. You want to create a nested route where /shop shows a Shop component and /shop/products shows a Products component inside Shop. Which setup correctly achieves this and ensures accessibility and responsiveness? A) Define routes with children array, use <router-view /> in Shop, and add ARIA roles and responsive CSS. B) Define separate routes for /shop and /shop/products without nesting, and use CSS media queries only. C) Use nested routes but omit <router-view /> in Shop and rely on v-if to show Products. D) Use nested routes with children but place <router-view /> outside Shop component.

hard

A. Use nested routes but place outside Shop component

B. Define separate routes without nesting and use only CSS media queries

C. Use nested routes but omit in Shop and use v-if for Products

D. Define routes with children array, use in Shop, add ARIA roles and responsive CSS

Solution

1. Step 1: Setup nested routes properly

   Use a children array in the /shop route to define /shop/products as a child route.

2. Step 2: Ensure Shop component includes <router-view />

   This allows Products component to render inside Shop when navigating to /shop/products.

3. Step 3: Add accessibility and responsiveness

   Use ARIA roles for landmarks and semantic HTML, plus responsive CSS (like Flexbox or Grid) to adapt layout on different screens.

4. Final Answer:

   Define routes with children array, use <router-view /> in Shop, add ARIA roles and responsive CSS -> Option D

5. Quick Check:

   Nested routes + router-view + accessibility + responsive CSS = Define routes with children array, use in Shop, add ARIA roles and responsive CSS [OK]

Hint: Nested routes need router-view in parent plus ARIA and responsive CSS [OK]

Common Mistakes:

• Omitting router-view in parent component
• Not adding ARIA roles for accessibility
• Ignoring responsive design in CSS
• Placing router-view outside parent component