dioxus/docs/guide/src/components/index.md

Introduction to Components

In the previous chapter, we learned about Elements and how they can be composed to create a basic user interface. Now, we'll learn how to group Elements together to form Components. We'll cover:

• What makes a Component
• How to model a component and its properties in Dioxus
• How to "think declaratively"

What is a component?

In short, a component is a special function that takes input properties and outputs an Element. Much like a function encapsulates some specific computation task, a Component encapsulates some specific rendering task – typically, rendering an isolated part of the user interface.

Real-world example

Take a look at a post on Reddit:

We can build this post as a component, consisting of multiple subcomponents. It has several inputs:

• The score
• The number of comments
• How long ago it was posted
• The url short address
• The title
• The username of the original poster

If we wanted to sketch out these requirements in Rust, we would start with a struct:

struct PostData {
    score: i32,
    comment_count: u32,
    post_time: Instant,
    url: String,
    title: String,
    original_poster_name: String
}

If we look at the layout of the component, we notice quite a few buttons and pieces of functionality:

• Upvote/Downvote
• View comments
• Share
• Save
• Hide
• Give award
• Report
• Crosspost
• Filter by site
• View article
• Visit user

If we included all this functionality in one rsx! call it would be huge! Instead, let's break the post down into some core pieces:

• VoteButton: Upvote/Downvote
• TitleCard: Title, Filter-By-Url
• MetaCard: Original Poster, Time Submitted
• ActionCard: View comments, Share, Save, Hide, Give award, Report, Crosspost

In this chapter, we'll learn how to define our own components.