You can inline the style inside the component as well:
<!-- begin snippet: js hide: false console: true babel: true -->
<!-- language: lang-js -->
const Spinner = () => (
<React.Fragment>
<style>
{`
.background {
fill: #555;
}
.line {
animation: PacMan 5s infinite;
fill: none;
stroke: #d26188;
stroke-width: 25;
}
.spinner {
animation: Spin 2s infinite linear;
}
@keyframes PacMan {
0% {
stroke-dasharray: 79px 79;
}
50% {
stroke-dasharray: 1px 79;
}
100% {
stroke-dasharray: 79px 79;
}
}
@keyframes Spin {
0% {
transform: rotate(0deg);
}
100% {
transform: rotate(360deg);
}
}
`}
</style>
<svg class="spinner" width="150" height="150" viewBox="0 0 100 100">
<circle class="background" r="24" cx="50" cy="50"></circle>
<path
class="line"
d="M 37.5,50 C 37.5,43.096441 43.096441,37.5 50,37.5 C 56.903559,37.5 62.5,43.096441 62.5,50 C 62.5,56.903559 56.903559,62.5 50,62.5 C 43.096441,62.5 37.5,56.903559 37.5,50"
></path>
</svg>
</React.Fragment>
)
ReactDOM.render(
<Spinner />,
root
)
<!-- language: lang-css -->
body {
align-items: center;
background: #333;
display: flex;
flex-direction: column;
justify-content: center;
height: 100vh;
}
<!-- language: lang-html -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>
<!-- end snippet -->
That's [*property spread notation*][1]. It was added in ES2018 (spread for arrays/iterables was earlier, ES2015), but it's been supported in React projects for along time via transpilation (as "[JSX spread attributes][2]" even though you could do it elsewhere, too, not just attributes).
`{...this.props}` *spreads out* the "own" enumerable properties in `props` as discrete properties on the `Modal` element you're creating. For instance, if `this.props` contained `a: 1` and `b: 2`, then
<Modal {...this.props} title='Modal heading' animation={false}>
would be the same as
<Modal a={this.props.a} b={this.props.b} title='Modal heading' animation={false}>
But it's dynamic, so whatever "own" properties are in `props` are included.
Since `children` is an "own" property in `props`, spread will include it. So if the component where this appears had child elements, they'll be passed on to `Modal`. Putting child elements between the opening tag and closing tags is just syntactic sugar — the good kind — for putting a `children` property in the opening tag. Example:
<!-- begin snippet: js hide: true console: true babel: true -->
<!-- language: lang-js -->
class Example extends React.Component {
render() {
const { className, children } = this.props;
return (
<div className={className}>
{children}
</div>
);
}
}
ReactDOM.render(
[
<Example className="first">
<span>Child in first</span>
</Example>,
<Example className="second" children={<span>Child in second</span>} />
],
document.getElementById("root")
);
<!-- language: lang-css -->
.first {
color: green;
}
.second {
color: blue;
}
<!-- language: lang-html -->
<div id="root"></div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<!-- end snippet -->
Spread notation is handy not only for that use case, but for creating a new object with most (or all) of the properties of an existing object — which comes up a lot when you're updating state, since you can't modify state directly:
this.setState(prevState => {
return {foo: {...prevState.foo, a: "updated"}};
});
That replaces `this.state.foo` with a new object with all the same properties as `foo` except the `a` property, which becomes `"updated"`:
<!-- begin snippet: js hide: true console: true babel: false -->
<!-- language: lang-js -->
const obj = {
foo: {
a: 1,
b: 2,
c: 3
}
};
console.log("original", obj.foo);
// Creates a NEW object and assigns it to `obj.foo`
obj.foo = {...obj.foo, a: "updated"};
console.log("updated", obj.foo);
<!-- language: lang-css -->
.as-console-wrapper {
max-height: 100% !important;
}
<!-- end snippet -->
[1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax
[2]: https://reactjs.org/docs/jsx-in-depth.html#spread-attributes
