Yesterday we built our first React app, and while it’s still fresh, let’s dive deeper into Components
and Props
.
To recap, React
is built as a component-based language. A lot of components
make up a React
app.
And Props
are how we can make Components
dynamic. Props
cannot be changed, however.
Creating a data set in React
Let’s start building on the basic React app we created yesterday.
We will make multiple components in the main App.js
file. In a best practice world, I would suggest moving components out into their files, but for now, it’s visually better to work like this until we get the hang of components
.
Let’s start by adding a data source to our file, an array of people.
We can add this array under our import
statements.
const people = [
{
firstName: 'Chris',
lastName: 'Bongers',
},
{
firstName: 'Hub',
lastName: 'Bongers',
},
{
firstName: 'Sanne',
lastName: 'Bongers',
},
];
Nothing fancy, just 3 people from my household.
What we want to achieve here is to show this data in a table
and add our own fantastic component
to render some avatar for each person.
Writing our first component in React
Now let’s change our App function to the following:
function App() {
return <Table data={people} />;
}
Way more straightforward than the previous code, but this won’t do anything and give errors.
React doesn’t know what a Table
element is… So let’s create our first component
: Table
.
We pass our people JSON object into this Component
and call it data this is the Prop
.
Above this function, we will add the following snippet:
const Table = ({data}) => (
<table className={'table'} cellSpacing={0} cellPadding={0}>
<tbody>
{data.map((row, i) => {
return <TableRow row={row} key={i} />;
})}
</tbody>
</table>
);
We use ES6
arrow functions, which is just a quicker way of writing a complete function
.
This component
is nothing fancy but returns an HTML table
element.
Then it maps each row inside our data object (which we passed in our basic App component
).
For each row in our data object, we then say return a component
called TableRow
and give it the props
row
and key.
- Note that
key
is not a prop we are passing through, but each unique list item or row item inReact
must have a unique identifier.
For our TableRow component
, we use the following snippet:
const TableRow = ({row}) => (
<tr>
<td>
<Avatar person={row} />
</td>
<td>{row.firstName}</td>
<td>{row.lastName}</td>
</tr>
);
Again, you would say nothing fancy. It accepts row
as a prop
and returns an HTML <tr>
with the rows firstName and lastName.
Then you see we added another Component
called Avatar
, and we give it a prop
called person
, which is our current row.
So let’s look at how this Avatar
component
looks like
const Avatar = ({person}) => {
const {firstName, lastName} = person;
let name = firstName.charAt(0).toUpperCase() + lastName.charAt(0).toUpperCase();
return <div className={'avatar'}>{name}</div>;
};
I set up the Avatar component
slightly differently to show you our options in React
.
We deconstruct a new const firstName
and lastName
from the person object.
This is the same we did in the TableRow
component as row.firstName
.
Then we define a new variable called name
. We get the first character off our firstName and convert it to uppercase. Then we do the same for the lastName.
We then return a div
with a class avatar
and pass the newly created variable name
to it.
This will render a div with CB for our first contact Chris Bongers.
You can see a demo here:
Feel free to download this part from GitHub.
Thank you for reading, and let’s connect!
Let me know what React topics you would like to see in more depth and feel free to subscribe to my email newsletter and connect on Facebook or Twitter.