SectionList for grouped data in React Native - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a SectionList in React Native?

SectionList is a component that renders a list with sections, allowing you to group data under headers for better organization and readability.

beginner

How do you define the data structure for a SectionList?

You provide an array of objects, where each object has a title (or key) for the section header and a data array containing the items for that section.

beginner

Which prop is used to render the header for each section in a SectionList?

The renderSectionHeader prop is a function that returns the UI for each section header.

intermediate

Why use SectionList instead of FlatList for grouped data?

SectionList automatically handles grouping and rendering section headers, making it easier to display grouped lists without manually managing headers.

beginner

What is the purpose of the keyExtractor prop in SectionList?

It provides a unique key for each item in the list to help React Native optimize rendering and track items efficiently.

What type of data structure does SectionList expect for its sections prop?

A A single object with keys as section titles

B A simple array of strings

C A flat array of numbers

D An array of objects with <code>title</code> and <code>data</code> arrays

SectionList requires an array where each element has a title (or similar) and a data array for items.

Which prop renders the items inside each section of a SectionList?

A renderSectionHeader

B renderItem

C renderFooter

D renderSeparator

renderItem defines how each item in the section's data array is displayed.

What happens if you omit the keyExtractor in a SectionList?

A React Native will use the index as key, which may cause rendering issues

B The app will crash immediately

C Section headers won't render

D Items will not display at all

Without a unique key, React Native falls back to using indexes, which can cause inefficient rendering or bugs.

Which of these is a benefit of using SectionList for grouped data?

A Automatic section headers rendering

B Supports infinite scrolling by default

C Built-in search functionality

D Automatic data sorting

SectionList helps by rendering section headers automatically for grouped data.

How do you style the section headers in a SectionList?

A By passing a style object to <code>sections</code>

B Using the <code>headerStyle</code> prop

C By customizing the component returned in <code>renderSectionHeader</code>

D SectionList does not support styling headers

You control header styles by returning a styled component inside renderSectionHeader.

Explain how to set up a SectionList to display grouped data with headers.

Think about how you organize a grocery list by categories.

Describe the role of keyExtractor in SectionList and why it is important.

Imagine labeling each item so you can find it quickly.