Create React Elements
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๐จโ๐ผ Let's convert this to use React! But don't worry, we won't be doing any JSX just
yet... You're going to use raw React APIs here.
In modern applications, you typically get React and React DOM files from a "package registry",
like npm where packages we use are (react and
react-dom).
A package registry is a centralized repository where developers can publish
and share reusable code packages.
To keep things simple for these exercises, we'll import React from slightly different locations:
public/react.js(accessed at/react.js)public/react-dom/client.js(accessed at/react-dom/client.js)
These files use a service called esm.sh to provide the React packages.
Don't worry too much about esm.sh for now - it's just helping us load React easily in these exercises.
Here's a simple example of how to use the React createElement API:
import { createElement } from '/react.js'
import { createRoot } from '/react-dom/client.js'
const elementProps = { id: 'element-id', children: 'Hello world!' }
const elementType = 'h1'
const reactElement = createElement(elementType, elementProps)
const root = createRoot(rootElement)
root.render(reactElement)
๐ฆ As a reminder, in a typical application, your import will be something
like
import { createRoot } from 'react-dom/client'
With that, a build tool or
importmap will handle resolving that to the
correct path.The "props" in
elementProps above is short for "properties". Props are a key concept
in React - they're the way we pass data into our elements. You can think of the element
type as a blueprint for the kind of React component to create, and the props are the
inputs that customize that element.children is a special prop in React. It represents the content inside an element.
You have a few ways to specify children:- As a prop (like in the first example above)
- As multiple arguments to
createElement - As an array
Here's an example showing the last two methods:
const elementProps = { id: 'element-id' }
const elementType = 'h1'
// Method 2: Multiple arguments
const reactElement1 = createElement(
elementType,
elementProps,
'Hello',
' ',
'world!',
)
// Method 3: Array of children
const children = ['Hello', ' ', 'world!']
const reactElement2 = createElement(elementType, elementProps, children)
createRoot(rootElement).render(reactElement1) // or reactElement2
Alright! Let's put this into practice!
๐ฐ Tip: Use
console.log(reactElement) to see what your created element looks
like. You might find the structure interesting!
