v-for with objects in Vue - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does v-for do when used with an object in Vue?

v-for loops over each key-value pair in the object, letting you access both the key and the value inside the loop.

beginner

How do you access the key and value inside a v-for loop over an object?

You write v-for="(value, key) in object". The first variable is the value, the second is the key.

intermediate

Why should you add a :key when using v-for with objects?

Adding :key helps Vue track each item uniquely for better performance and correct updates.

beginner

What happens if you only use v-for="value in object" without the key?

You can loop over values, but you won't know the keys. Sometimes keys are important to show or use.

beginner

Show a simple example of v-for looping over an object with keys and values.

<pre>&lt;template&gt;
  &lt;ul&gt;
    &lt;li v-for="(value, key) in userInfo" :key="key"&gt;
      {{ key }}: {{ value }}
    &lt;/li&gt;
  &lt;/ul&gt;
&lt;/template&gt;

&lt;script setup&gt;
const userInfo = {
  name: 'Anna',
  age: 28,
  city: 'Paris'
}
&lt;/script&gt;</pre>

In Vue, how do you write v-for to loop over an object and get both key and value?

A v-for="value in object"

B v-for="key in object"

C v-for="object in (key, value)"

D v-for="(value, key) in object"

The correct syntax is v-for="(value, key) in object" to get both value and key.

Why is it important to add :key when using v-for with objects?

A To add a CSS class

B To make the text bold

C To help Vue track each item uniquely

D It is not important

:key helps Vue identify each item uniquely for efficient updates.

What will happen if you use v-for="value in object" without the key?

A You get only the values, no keys

B You get only the keys, no values

C It causes an error

D It loops over array indexes

Using only one variable loops over values, keys are not accessible.

Which of these is a valid object to loop over with v-for?

A { name: 'Tom', age: 30 }

B [ 'Tom', 30 ]

C 'Tom'

D null

Only objects with key-value pairs like { name: 'Tom', age: 30 } can be looped over with key and value.

What is the order of variables in v-for="(value, key) in object"?

A Only value

B Value first, then key

C Only key

D Key first, then value

The first variable is the value, the second is the key.

Explain how to use v-for to loop over an object in Vue and why you might want to include both key and value.

Think about how you get both parts of an object when looping.

Describe why adding a unique :key is important when using v-for with objects in Vue.

Consider how Vue updates the list when data changes.