100 lines
2.4 KiB
Markdown
100 lines
2.4 KiB
Markdown
---
|
|
title: Alert
|
|
tags: components,state,effect,beginner
|
|
---
|
|
|
|
Creates an alert component with `type` prop.
|
|
|
|
- Define appropriate CSS styles and animations for the component's elements.
|
|
- Use the `React.useState()` hook to create the `isShown` and `isLeaving` state variables and set their values to `false`.
|
|
- Define `timeoutId` to keep the timer instance for clearing on component unmount.
|
|
- Use the `React.useEffect()` hook to update the value of `isShown` to `true` and clear interval by using `timeoutId` when component is unmounted.
|
|
- Define `closeAlert` function to set the component is removed from DOM by displaying fading out animation and set `isShown` to `false` via `setTimeout()`.
|
|
- Define the component, which renders the alert component with user defined `message` and a close button to remove the component from DOM.
|
|
|
|
```css
|
|
@keyframes leave {
|
|
0% { opacity: 1 }
|
|
100% { opacity: 0 }
|
|
}
|
|
|
|
.alert {
|
|
padding: 0.75rem 0.5rem;
|
|
margin-bottom: 0.5rem;
|
|
text-align: left;
|
|
padding-right: 40px;
|
|
border-radius: 4px;
|
|
font-size: 16px;
|
|
position: relative;
|
|
}
|
|
|
|
.alert.warning{
|
|
color: #856404;
|
|
background-color: #fff3cd;
|
|
border-color: #ffeeba;
|
|
}
|
|
|
|
.alert.error{
|
|
color: #721c24;
|
|
background-color: #f8d7da;
|
|
border-color: #f5c6cb;
|
|
}
|
|
|
|
.alert.leaving{
|
|
animation: leave 0.5s forwards;
|
|
}
|
|
|
|
.alert .close {
|
|
position: absolute;
|
|
top: 0;
|
|
right: 0;
|
|
padding: 0 0.75rem;
|
|
color: #333;
|
|
border: 0;
|
|
height: 100%;
|
|
cursor: pointer;
|
|
background: none;
|
|
font-weight: 600;
|
|
font-size: 16px;
|
|
}
|
|
|
|
.alert .close:after{
|
|
content: 'x';
|
|
}
|
|
```
|
|
|
|
```jsx
|
|
const Alert = ({ isDefaultShown = false, timeout = 250, type, message }) => {
|
|
const [isShown, setIsShown] = React.useState(isDefaultShown);
|
|
const [isLeaving, setIsLeaving] = React.useState(false);
|
|
|
|
let timeoutId = null;
|
|
|
|
React.useEffect(() => {
|
|
setIsShown(true);
|
|
return () => {
|
|
clearTimeout(timeoutId);
|
|
};
|
|
}, [isDefaultShown, timeout, timeoutId]);
|
|
|
|
const closeAlert = () => {
|
|
setIsLeaving(true);
|
|
timeoutId = setTimeout(() => {
|
|
setIsLeaving(false);
|
|
setIsShown(false);
|
|
}, timeout);
|
|
};
|
|
|
|
return isShown && (
|
|
<div className={`alert ${type} ${isLeaving ? 'leaving' : ''}`} role="alert">
|
|
<button className="close" onClick={closeAlert} />
|
|
{message}
|
|
</div>
|
|
);
|
|
};
|
|
```
|
|
|
|
```jsx
|
|
ReactDOM.render(<Alert type="info" message="This is info" />, document.getElementById('root'));
|
|
```
|