Vue.js • Chapter 10 • Foundations to Advanced
List Rendering
Each topic includes substantial explanation, ten focused examples, its own Vue code example, step-by-step reasoning, expected behavior, and practice.
10.1 v-for with Arrays
v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Arrays and trace how it changes the rendered interface. In Chapter 10, trace the value or control flow from its source to the rendered interface so you can explain why Vue changes the screen.
For v-for with Arrays in Chapter 10, inspect reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Keep writable state ownership explicit, derive values when possible, and separate display calculations from network, DOM, storage, timer, or other external work.
This lesson connects v-for with Arrays to list rendering. Start with one working case, verify the expected output, then add one edge case and explain what Vue tracks, reuses, creates, removes, or updates.
Concept in plain language
v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Arrays and trace how it changes the rendered interface.
10 teaching examples
Example 1: Smallest useful case
Build the smallest photo gallery that demonstrates v-for with Arrays. Keep one input and one visible result, then explain reactive inputs, component ownership, rendered output, edge cases, and what causes another update. v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Arrays and trace how it changes the rendered interface. This is example 1 for Chapter 10, topic 1.
Example 2: Change one reactive value
Change one value involved in v-for with Arrays inside the notification center. Predict what Vue will update before running it, then compare the prediction with the rendered result.
Example 3: Parent-child comparison
Use v-for with Arrays across two components in the task board. Compare which component owns the writable data and which component only receives or presents it.
Example 4: Edge case
Add an empty, missing, invalid, delayed, or rapidly changing value to the language selector. Handle the v-for with Arrays edge case explicitly instead of leaving stale output.
Example 5: Accessibility review
Use v-for with Arrays in the quiz screen while checking semantic HTML, labels, focus order, keyboard access, and understandable status feedback. v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Arrays and trace how it changes the rendered interface. This is example 5 for Chapter 10, topic 1.
Example 6: State ownership review
Remove duplicated state from the analytics view. For v-for with Arrays, derive values when possible and keep the writable source with the component or store that owns it.
Example 7: Slow-network scenario
Assume the support form has a slow request while using v-for with Arrays. Decide what remains interactive, what shows pending feedback, and how stale responses are prevented.
Example 8: Refactoring exercise
Extract the v-for with Arrays responsibility from a crowded course dashboard into a focused component or composable with a narrow API.
Example 9: Performance experiment
Measure the profile editor before optimizing v-for with Arrays. Check reactive work, repeated calculations, list size, component updates, and user-visible delay.
Example 10: Production review
Review v-for with Arrays in the search panel for errors, security, localization, RTL, narrow screens, accessibility, and what monitoring should report. v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Arrays and trace how it changes the rendered interface. This is example 10 for Chapter 10, topic 1.
Vue code example
<script setup>
import { ref } from 'vue'
const topic = "v-for with Arrays"
const active = ref(false)
</script>
<template>
<section><h2>{{ topic }}</h2><button :aria-pressed="active" @click="active=!active">Toggle state</button><p>{{ active ? 'Active' : 'Inactive' }}</p></section>
</template>Step-by-step code explanation
- Identify the Vue responsibility demonstrated by v-for with Arrays.
- Read the reactive state, props, route/store input, or injected value before the template.
- Trace the event, dependency, watcher, lifecycle hook, or navigation action that changes the display.
- Test one normal path and one edge case, including cleanup when external work is involved.
- Confirm accessibility, mobile width, and RTL behavior for user-facing controls and translated text.
Expected behavior: A small Vue interface demonstrates v-for with Arrays and updates according to the interaction or data in the example.
Practice exercise
Create a small Vue feature focused on v-for with Arrays from Chapter 10. Predict the result before running it, test one edge case, and explain which reactive value, prop, event, route, store, or lifecycle step caused the update. Then check accessibility, narrow-screen width, and RTL behavior where relevant.
10.2 v-for with Objects
v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Objects and trace how it changes the rendered interface. In Chapter 10, trace the value or control flow from its source to the rendered interface so you can explain why Vue changes the screen.
For v-for with Objects in Chapter 10, inspect reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Keep writable state ownership explicit, derive values when possible, and separate display calculations from network, DOM, storage, timer, or other external work.
This lesson connects v-for with Objects to list rendering. Start with one working case, verify the expected output, then add one edge case and explain what Vue tracks, reuses, creates, removes, or updates.
Concept in plain language
v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Objects and trace how it changes the rendered interface.
10 teaching examples
Example 1: Smallest useful case
Build the smallest language selector that demonstrates v-for with Objects. Keep one input and one visible result, then explain reactive inputs, component ownership, rendered output, edge cases, and what causes another update. v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Objects and trace how it changes the rendered interface. This is example 1 for Chapter 10, topic 2.
Example 2: Change one reactive value
Change one value involved in v-for with Objects inside the quiz screen. Predict what Vue will update before running it, then compare the prediction with the rendered result.
Example 3: Parent-child comparison
Use v-for with Objects across two components in the analytics view. Compare which component owns the writable data and which component only receives or presents it.
Example 4: Edge case
Add an empty, missing, invalid, delayed, or rapidly changing value to the support form. Handle the v-for with Objects edge case explicitly instead of leaving stale output.
Example 5: Accessibility review
Use v-for with Objects in the course dashboard while checking semantic HTML, labels, focus order, keyboard access, and understandable status feedback. v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Objects and trace how it changes the rendered interface. This is example 5 for Chapter 10, topic 2.
Example 6: State ownership review
Remove duplicated state from the profile editor. For v-for with Objects, derive values when possible and keep the writable source with the component or store that owns it.
Example 7: Slow-network scenario
Assume the search panel has a slow request while using v-for with Objects. Decide what remains interactive, what shows pending feedback, and how stale responses are prevented.
Example 8: Refactoring exercise
Extract the v-for with Objects responsibility from a crowded shopping cart into a focused component or composable with a narrow API.
Example 9: Performance experiment
Measure the lesson tracker before optimizing v-for with Objects. Check reactive work, repeated calculations, list size, component updates, and user-visible delay.
Example 10: Production review
Review v-for with Objects in the booking form for errors, security, localization, RTL, narrow screens, accessibility, and what monitoring should report. v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Objects and trace how it changes the rendered interface. This is example 10 for Chapter 10, topic 2.
Vue code example
<script setup>
import { ref } from 'vue'
const topic = "v-for with Objects"
const active = ref(false)
</script>
<template>
<section><h2>{{ topic }}</h2><button :aria-pressed="active" @click="active=!active">Toggle state</button><p>{{ active ? 'Active' : 'Inactive' }}</p></section>
</template>Step-by-step code explanation
- Identify the Vue responsibility demonstrated by v-for with Objects.
- Read the reactive state, props, route/store input, or injected value before the template.
- Trace the event, dependency, watcher, lifecycle hook, or navigation action that changes the display.
- Test one normal path and one edge case, including cleanup when external work is involved.
- Confirm accessibility, mobile width, and RTL behavior for user-facing controls and translated text.
Expected behavior: A small Vue interface demonstrates v-for with Objects and updates according to the interaction or data in the example.
Practice exercise
Create a small Vue feature focused on v-for with Objects from Chapter 10. Predict the result before running it, test one edge case, and explain which reactive value, prop, event, route, store, or lifecycle step caused the update. Then check accessibility, narrow-screen width, and RTL behavior where relevant.
10.3 Using key
Using key is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements. In Chapter 10, trace the value or control flow from its source to the rendered interface so you can explain why Vue changes the screen.
For Using key in Chapter 10, inspect reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Keep writable state ownership explicit, derive values when possible, and separate display calculations from network, DOM, storage, timer, or other external work.
This lesson connects Using key to list rendering. Start with one working case, verify the expected output, then add one edge case and explain what Vue tracks, reuses, creates, removes, or updates.
Concept in plain language
Using key is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements.
10 teaching examples
Example 1: Smallest useful case
Build the smallest support form that demonstrates Using key. Keep one input and one visible result, then explain reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Using key is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements. This is example 1 for Chapter 10, topic 3.
Example 2: Change one reactive value
Change one value involved in Using key inside the course dashboard. Predict what Vue will update before running it, then compare the prediction with the rendered result.
Example 3: Parent-child comparison
Use Using key across two components in the profile editor. Compare which component owns the writable data and which component only receives or presents it.
Example 4: Edge case
Add an empty, missing, invalid, delayed, or rapidly changing value to the search panel. Handle the Using key edge case explicitly instead of leaving stale output.
Example 5: Accessibility review
Use Using key in the shopping cart while checking semantic HTML, labels, focus order, keyboard access, and understandable status feedback. Using key is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements. This is example 5 for Chapter 10, topic 3.
Example 6: State ownership review
Remove duplicated state from the lesson tracker. For Using key, derive values when possible and keep the writable source with the component or store that owns it.
Example 7: Slow-network scenario
Assume the booking form has a slow request while using Using key. Decide what remains interactive, what shows pending feedback, and how stale responses are prevented.
Example 8: Refactoring exercise
Extract the Using key responsibility from a crowded message panel into a focused component or composable with a narrow API.
Example 9: Performance experiment
Measure the admin table before optimizing Using key. Check reactive work, repeated calculations, list size, component updates, and user-visible delay.
Example 10: Production review
Review Using key in the photo gallery for errors, security, localization, RTL, narrow screens, accessibility, and what monitoring should report. Using key is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements. This is example 10 for Chapter 10, topic 3.
Vue code example
<script setup>
import { ref } from 'vue'
const topic = "Using key"
const active = ref(false)
</script>
<template>
<section><h2>{{ topic }}</h2><button :aria-pressed="active" @click="active=!active">Toggle state</button><p>{{ active ? 'Active' : 'Inactive' }}</p></section>
</template>Step-by-step code explanation
- Identify the Vue responsibility demonstrated by Using key.
- Read the reactive state, props, route/store input, or injected value before the template.
- Trace the event, dependency, watcher, lifecycle hook, or navigation action that changes the display.
- Test one normal path and one edge case, including cleanup when external work is involved.
- Confirm accessibility, mobile width, and RTL behavior for user-facing controls and translated text.
Expected behavior: A small Vue interface demonstrates Using key and updates according to the interaction or data in the example.
Practice exercise
Create a small Vue feature focused on Using key from Chapter 10. Predict the result before running it, test one edge case, and explain which reactive value, prop, event, route, store, or lifecycle step caused the update. Then check accessibility, narrow-screen width, and RTL behavior where relevant.
10.4 Filtering and Sorting Lists
Filtering and Sorting Lists is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements. In Chapter 10, trace the value or control flow from its source to the rendered interface so you can explain why Vue changes the screen.
For Filtering and Sorting Lists in Chapter 10, inspect reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Keep writable state ownership explicit, derive values when possible, and separate display calculations from network, DOM, storage, timer, or other external work.
This lesson connects Filtering and Sorting Lists to list rendering. Start with one working case, verify the expected output, then add one edge case and explain what Vue tracks, reuses, creates, removes, or updates.
Concept in plain language
Filtering and Sorting Lists is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements.
10 teaching examples
Example 1: Smallest useful case
Build the smallest search panel that demonstrates Filtering and Sorting Lists. Keep one input and one visible result, then explain reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Filtering and Sorting Lists is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements. This is example 1 for Chapter 10, topic 4.
Example 2: Change one reactive value
Change one value involved in Filtering and Sorting Lists inside the shopping cart. Predict what Vue will update before running it, then compare the prediction with the rendered result.
Example 3: Parent-child comparison
Use Filtering and Sorting Lists across two components in the lesson tracker. Compare which component owns the writable data and which component only receives or presents it.
Example 4: Edge case
Add an empty, missing, invalid, delayed, or rapidly changing value to the booking form. Handle the Filtering and Sorting Lists edge case explicitly instead of leaving stale output.
Example 5: Accessibility review
Use Filtering and Sorting Lists in the message panel while checking semantic HTML, labels, focus order, keyboard access, and understandable status feedback. Filtering and Sorting Lists is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements. This is example 5 for Chapter 10, topic 4.
Example 6: State ownership review
Remove duplicated state from the admin table. For Filtering and Sorting Lists, derive values when possible and keep the writable source with the component or store that owns it.
Example 7: Slow-network scenario
Assume the photo gallery has a slow request while using Filtering and Sorting Lists. Decide what remains interactive, what shows pending feedback, and how stale responses are prevented.
Example 8: Refactoring exercise
Extract the Filtering and Sorting Lists responsibility from a crowded notification center into a focused component or composable with a narrow API.
Example 9: Performance experiment
Measure the task board before optimizing Filtering and Sorting Lists. Check reactive work, repeated calculations, list size, component updates, and user-visible delay.
Example 10: Production review
Review Filtering and Sorting Lists in the language selector for errors, security, localization, RTL, narrow screens, accessibility, and what monitoring should report. Filtering and Sorting Lists is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements. This is example 10 for Chapter 10, topic 4.
Vue code example
<script setup>
import { ref } from 'vue'
const topic = "Filtering and Sorting Lists"
const active = ref(false)
</script>
<template>
<section><h2>{{ topic }}</h2><button :aria-pressed="active" @click="active=!active">Toggle state</button><p>{{ active ? 'Active' : 'Inactive' }}</p></section>
</template>Step-by-step code explanation
- Identify the Vue responsibility demonstrated by Filtering and Sorting Lists.
- Read the reactive state, props, route/store input, or injected value before the template.
- Trace the event, dependency, watcher, lifecycle hook, or navigation action that changes the display.
- Test one normal path and one edge case, including cleanup when external work is involved.
- Confirm accessibility, mobile width, and RTL behavior for user-facing controls and translated text.
Expected behavior: A small Vue interface demonstrates Filtering and Sorting Lists and updates according to the interaction or data in the example.
Practice exercise
Create a small Vue feature focused on Filtering and Sorting Lists from Chapter 10. Predict the result before running it, test one edge case, and explain which reactive value, prop, event, route, store, or lifecycle step caused the update. Then check accessibility, narrow-screen width, and RTL behavior where relevant.
10.5 v-for with Components
v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Components and trace how it changes the rendered interface. In Chapter 10, trace the value or control flow from its source to the rendered interface so you can explain why Vue changes the screen.
For v-for with Components in Chapter 10, inspect reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Keep writable state ownership explicit, derive values when possible, and separate display calculations from network, DOM, storage, timer, or other external work.
This lesson connects v-for with Components to list rendering. Start with one working case, verify the expected output, then add one edge case and explain what Vue tracks, reuses, creates, removes, or updates.
Concept in plain language
v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Components and trace how it changes the rendered interface.
10 teaching examples
Example 1: Smallest useful case
Build the smallest booking form that demonstrates v-for with Components. Keep one input and one visible result, then explain reactive inputs, component ownership, rendered output, edge cases, and what causes another update. v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Components and trace how it changes the rendered interface. This is example 1 for Chapter 10, topic 5.
Example 2: Change one reactive value
Change one value involved in v-for with Components inside the message panel. Predict what Vue will update before running it, then compare the prediction with the rendered result.
Example 3: Parent-child comparison
Use v-for with Components across two components in the admin table. Compare which component owns the writable data and which component only receives or presents it.
Example 4: Edge case
Add an empty, missing, invalid, delayed, or rapidly changing value to the photo gallery. Handle the v-for with Components edge case explicitly instead of leaving stale output.
Example 5: Accessibility review
Use v-for with Components in the notification center while checking semantic HTML, labels, focus order, keyboard access, and understandable status feedback. v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Components and trace how it changes the rendered interface. This is example 5 for Chapter 10, topic 5.
Example 6: State ownership review
Remove duplicated state from the task board. For v-for with Components, derive values when possible and keep the writable source with the component or store that owns it.
Example 7: Slow-network scenario
Assume the language selector has a slow request while using v-for with Components. Decide what remains interactive, what shows pending feedback, and how stale responses are prevented.
Example 8: Refactoring exercise
Extract the v-for with Components responsibility from a crowded quiz screen into a focused component or composable with a narrow API.
Example 9: Performance experiment
Measure the analytics view before optimizing v-for with Components. Check reactive work, repeated calculations, list size, component updates, and user-visible delay.
Example 10: Production review
Review v-for with Components in the support form for errors, security, localization, RTL, narrow screens, accessibility, and what monitoring should report. v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Components and trace how it changes the rendered interface. This is example 10 for Chapter 10, topic 5.
Vue code example
<script setup>
import { ref } from 'vue'
const topic = "v-for with Components"
const active = ref(false)
</script>
<template>
<section><h2>{{ topic }}</h2><button :aria-pressed="active" @click="active=!active">Toggle state</button><p>{{ active ? 'Active' : 'Inactive' }}</p></section>
</template>Step-by-step code explanation
- Identify the Vue responsibility demonstrated by v-for with Components.
- Read the reactive state, props, route/store input, or injected value before the template.
- Trace the event, dependency, watcher, lifecycle hook, or navigation action that changes the display.
- Test one normal path and one edge case, including cleanup when external work is involved.
- Confirm accessibility, mobile width, and RTL behavior for user-facing controls and translated text.
Expected behavior: A small Vue interface demonstrates v-for with Components and updates according to the interaction or data in the example.
Practice exercise
Create a small Vue feature focused on v-for with Components from Chapter 10. Predict the result before running it, test one edge case, and explain which reactive value, prop, event, route, store, or lifecycle step caused the update. Then check accessibility, narrow-screen width, and RTL behavior where relevant.
Chapter 10 review — 10 questions and answers
1. What is the purpose of v-for with Arrays?
Answer: v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Arrays and trace how it changes the rendered interface.
2. What should you inspect when v-for with Arrays behaves unexpectedly?
Answer: Inspect reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Reduce the feature to a small component and trace reactive input through the rendered result.
3. What is the purpose of v-for with Objects?
Answer: v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Objects and trace how it changes the rendered interface.
4. What should you inspect when v-for with Objects behaves unexpectedly?
Answer: Inspect reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Reduce the feature to a small component and trace reactive input through the rendered result.
5. What is the purpose of Using key?
Answer: Using key is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements.
6. What should you inspect when Using key behaves unexpectedly?
Answer: Inspect reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Reduce the feature to a small component and trace reactive input through the rendered result.
7. What is the purpose of Filtering and Sorting Lists?
Answer: Filtering and Sorting Lists is a focused part of Vue application design in Chapter 10. Study its inputs, reactive dependencies, component ownership, rendered result, edge cases, and cleanup requirements.
8. What should you inspect when Filtering and Sorting Lists behaves unexpectedly?
Answer: Inspect reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Reduce the feature to a small component and trace reactive input through the rendered result.
9. What is the purpose of v-for with Components?
Answer: v-for repeats markup for items, while a stable key helps Vue preserve the identity of each rendered item. In Chapter 10, apply this definition specifically to v-for with Components and trace how it changes the rendered interface.
10. What should you inspect when v-for with Components behaves unexpectedly?
Answer: Inspect reactive inputs, component ownership, rendered output, edge cases, and what causes another update. Reduce the feature to a small component and trace reactive input through the rendered result.