What are props in React - Interactive Quiz & Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to pass a prop named name with value "Alice" to the Greeting component.

React

function App() {
  return <Greeting [1] />;
}

Drag options to blanks, or click blank then click option'

Avalue="Alice"

Bname="Alice"

Cprop="Alice"

Dtext="Alice"

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect attribute names like 'value' or 'prop' instead of the prop name.

Props are like attributes you add to components. Here, name="Alice" passes the value "Alice" as a prop called name.

2fill in blank

medium

Complete the code to access the name prop inside the Greeting component.

React

function Greeting([1]) {
  return <h1>Hello, {name}!</h1>;
}

Drag options to blanks, or click blank then click option'

Aname

Bprops

C{name}

Dprops.name

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'props' without destructuring and then trying to use 'name' directly.

Using {name} in the function parameter extracts the name prop directly for easy use.

3fill in blank

hard

Fix the error in the code to correctly display the name prop.

React

function Greeting(props) {
  return <h1>Hello, [1]!</h1>;
}

Drag options to blanks, or click blank then click option'

Aprops[name]

Bname

Cprops.name

Dprops->name

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to use 'name' directly without destructuring or accessing it from props.

When using props as a parameter, access the name prop with props.name.

4fill in blank

hard

Fill both blanks to pass two props firstName and age to the User component.

React

function App() {
  return <User [1] [2] />;
}

Drag options to blanks, or click blank then click option'

AfirstName="Bob"

Bage={30}

Cname="Bob"

Dyears={30}

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong prop names or passing numbers as strings.

Props are passed as attributes. Here, firstName="Bob" and age={30} pass two props correctly.

5fill in blank

hard

Fill all three blanks to create a Profile component that receives props and displays them.

React

function Profile([1], [2], [3]) {
  return (
    <div>
      <h2>{firstName} {lastName}</h2>
      <p>Age: {age}</p>
    </div>
  );
}

Drag options to blanks, or click blank then click option'

AfirstName

Bage

ClastName

Dprops

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'props' instead of destructuring individual props.

The component destructures the props firstName, lastName, and age to use them inside.

Practice

1. What are props in React?

easy

A. Data passed from a parent component to a child component

B. A way to store component state internally

C. Functions that update the component's state

D. A method to style components

Solution

1. Step 1: Understand the role of props

   Props are used to send data from a parent component down to a child component in React.

2. Step 2: Differentiate props from state and methods

   Props are not for storing state or styling; they are inputs like function arguments.

3. Final Answer:

   Data passed from a parent component to a child component -> Option A

4. Quick Check:

   Props = Parent to child data [OK]

Hint: Props are like function arguments passed down [OK]

Common Mistakes:

• Confusing props with state
• Thinking props change inside the child
• Believing props are used for styling

2. Which of the following is the correct way to pass a prop named title with value "Hello" to a component Greeting?

easy

A.

B.

C.

D.

Solution

1. Step 1: Recognize JSX prop syntax

   Props are passed as attributes with key-value pairs inside JSX tags, using quotes for strings.

2. Step 2: Check each option's syntax

   correctly uses title="Hello". misses the key, C uses unquoted value, D misses quotes.

3. Final Answer:

   <Greeting title="Hello" /> -> Option D

4. Quick Check:

   Props syntax = key="value" [OK]

Hint: Props look like HTML attributes with quotes [OK]

Common Mistakes:

• Omitting the prop name
• Not quoting string values
• Using curly braces without variables

3. Given this component:

function Welcome(props) {
  return <h1>Hello, {props.name}!</h1>;
}

// Usage:
<Welcome name="Alice" />

What will be rendered on the screen?

medium

A. Hello, props.name!

B. Hello, !

C. Hello, Alice!

D. Error: props is undefined

Solution

1. Step 1: Identify how props are used in the component

   The component uses props.name inside JSX to display the passed name.

2. Step 2: Check the usage of the component

   The component is called with name="Alice", so props.name equals "Alice".

3. Final Answer:

   Hello, Alice! -> Option C

4. Quick Check:

   props.name = Alice [OK]

Hint: Props values appear where you use {props.key} [OK]

Common Mistakes:

• Printing the literal string 'props.name'
• Forgetting to pass the prop
• Assuming props is undefined

4. What is wrong with this React component usage?

function Message(props) {
  return <p>{props.text}</p>;
}

// Usage:
<Message text=Hello />

medium

A. The function should return a string, not JSX

B. The prop value Hello should be in quotes

C. Props cannot be used inside <p> tags

D. The component name should be lowercase

Solution

1. Step 1: Check the prop syntax in usage

   The prop text=Hello is missing quotes around the string value.

2. Step 2: Recall JSX rules for string props

   String props must be quoted like text="Hello" or wrapped in curly braces if a variable.

3. Final Answer:

   The prop value Hello should be in quotes -> Option B

4. Quick Check:

   String props need quotes [OK]

Hint: Always quote string props in JSX [OK]

Common Mistakes:

• Leaving string props unquoted
• Using lowercase component names
• Misunderstanding JSX return types

5. You want to create a reusable Button component that shows different labels based on props. Which approach correctly uses props to achieve this?

function Button(props) {
  return <button>{props.label}</button>;
}

// Usage:
<Button label="Save" />
<Button label="Cancel" />

hard

A. This approach works because props.label changes the button text dynamically

B. This approach is wrong because props cannot be used inside button tags

C. You must use state instead of props to change button labels

D. Button labels must be hardcoded inside the component

Solution

1. Step 1: Understand props usage for dynamic content

   Props allow passing different values to the same component to show varied content.

2. Step 2: Verify the example usage

   The Button component uses props.label inside the button, and different labels are passed in usage.

3. Final Answer:

   This approach works because props.label changes the button text dynamically -> Option A

4. Quick Check:

   Props enable reusable components [OK]

Hint: Use props to customize component content easily [OK]

Common Mistakes:

• Thinking props can't change displayed text
• Confusing props with state for static labels
• Hardcoding values inside components