From 1154b5dcd4d3ac76d98fe0cc90515f54ae04fc78 Mon Sep 17 00:00:00 2001
From: Angelos Chalaris <chalarangelo@gmail.com>
Date: Tue, 10 Sep 2019 09:07:29 +0300
Subject: [PATCH] Add RippleButton

A button component with a ripple animation on click.
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 snippets/RippleButton.md | 120 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 snippets/RippleButton.md

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+---
+title: RippleButton
+tags: visual,state,effect,intermediate
+---
+
+### RippleButton
+
+Renders a button that animates a ripple effect when clicked.
+
+- Define some appropriate CSS styles and an animation for the ripple effect.
+- Use the `React.useState()` hook to create appropriate variables and setters for the pointer's coordinates and for the animation state of the button.
+- Use the `React.useEffect()` hook to change the state every time the `coords` state variable changes, starting the animation.
+- Use `setTimeout()` in the previous hook to clear the animation after it's done playing.
+- Use the `React.useEffect()` hook a second time to reset `coords` whenever the `isRippling` state variable is `false.`
+- Handle the `onClick` event by updating the `coords` state variable and calling the passed callback.
+- Finally, render a `<button>` with one or two `<span>` elements, setting the position of the `.ripple` element based on the `coords` state variable.
+
+```css
+.ripple-button {
+  border-radius: 4px;
+  border: none;
+  margin: 8px;
+  padding: 14px 24px;
+  background: #1976d2;
+  color: #fff;
+  overflow: hidden;
+  position: relative;
+  cursor: pointer;
+}
+
+.ripple-button > .ripple {
+  width: 20px;
+  height: 20px;
+  position: absolute;
+  background: #63a4ff;
+  display: block;
+  content: "";
+  border-radius: 9999px;
+  opacity: 1;
+  animation: 1.2s ease 1 forwards ripple-effect;
+}
+
+@keyframes ripple-effect {
+  0% {
+    transform: scale(1);
+    opacity: 1;
+  }
+  50% {
+    transform: scale(10);
+    opacity: 0.375;
+  }
+  100% {
+    transform: scale(35);
+    opacity: 0;
+  }
+}
+
+.ripple-button > .content {
+  position: relative;
+  z-index: 2;
+}
+
+```
+
+```jsx
+function RippleButton({ children, onClick }) {
+  const [coords, setCoords] = React.useState({ x: -1, y: -1 });
+  const [isRippling, setIsRippling] = React.useState(false);
+
+  React.useEffect(
+    () => {
+      if (coords.x !== -1 && coords.y !== -1) {
+        setIsRippling(true);
+        setTimeout(() => setIsRippling(false), 1200);
+      } else setIsRippling(false);
+    },
+    [coords]
+  );
+
+  React.useEffect(
+    () => {
+      if (!isRippling) setCoords({ x: -1, y: -1 });
+    },
+    [isRippling]
+  );
+
+  return (
+    <button
+      className="ripple-button"
+      onClick={e => {
+        var rect = e.target.getBoundingClientRect();
+        var x = e.clientX - rect.left;
+        var y = e.clientY - rect.top;
+        setCoords({ x, y });
+        onClick && onClick(e);
+      }}
+    >
+      {isRippling ? (
+        <span
+          className="ripple"
+          style={{
+            left: coords.x + 10,
+            top: coords.y
+          }}
+        />
+      ) : (
+        ""
+      )}
+      <span className="content">{children}</span>
+    </button>
+  );
+}
+```
+
+```jsx
+ReactDOM.render(
+  <RippleButton onClick={e => console.log(e)}>Click me</RippleButton>,
+  document.getElementById('root')
+);
+```