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Here's How You can Animate React with Framer Motion by@koss-lebedev
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Here's How You can Animate React with Framer Motion

by Konstantin LebedevSeptember 13th, 2019
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Framer-motion is a library that powers animations in Framer. It’s now available as an independent package that we can use in React applications. It has a simple declarative API that makes it easy to create and orchestrate complex animations with the minimal amount of code. In this article, we’ll start with very basic animations and gradually move to the more advanced ones. To create the simplest animation, we can specify a property that accepts an object with CSS properties that we want to animate.

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 is a library that powers animations in , and it’s now available as an independent package that we can use in React applications. It has a very simple declarative API that makes it easy to create and orchestrate complex animations with the minimal amount of code. In this article, we’ll start with very basic animations and gradually move to the more advanced ones.

Note: animation examples in the article may not look smooth because of a low frame rate of GIF images. Rest assured, real animation are butter-smooth. You can play with them in the 

.

Setup

We can start with framer-motion by simply installing it with 

yarn add framer-motion
command.

To animate elements, we’ll need to ditch primitive HTML elements (

div
span
path
, etc.) in favor of their “motion-infused” counterparts - 
motion.div
motion.span
motion.path
, etc. These elements expose the properties that we’ll need to add our animations.

Get things moving

To create the simplest animation, we can specify 

animate
 property that accepts an object with CSS properties that we want to animate. This is how we can animate opacity and background color of the 
div
:

import { motion } from "framer-motion";

const One = () => (
  <motion.div
    className="rectangle"
    animate={{
      opacity: 0.5,
      background: "#ff00b1"
    }}
  />
);

The properties that we pass to 

animate
 represent the final state of the animation. Framer-motion will infer the initial state based on the specified CSS properties, or their defaults. For example, default opacity for CSS elements is 
1
(even if we don’t set it explicitly), so framer-motion knows how to animate it down to 
0.5
.

We can also set the initial values of animatable CSS properties using 

initial
prop. It also accepts an object with CSS properties that will tell framer-motion what initial values should be like. In the example below, we fade in the rectangle by animating 
y
 and 
opacity
 properties:

const Two = () => (
  <motion.div
    className="rectangle"
    initial={{
      opacity: 0,
      y: 50
    }}
    animate={{
      opacity: 1,
      y: 0
    }}
  />
);

It’s worth mentioning that property 

y
 is special - it’s not a real CSS property, but framer-motion understands it. There are a bunch of CSS 
transform
-related properties that have shortcuts in framer-motion, so when we change 
y
property, we actually apply animation to 
transform: translateY()
 property. Similarly, there are 
scale
rotate
scaleX
scaleY
 and some other properties, you can find the complete list .

Animating state changes

The animations that we’ve done so far only run when components mount. Now let’s see how we can animate elements when some internal state changes.

We can set 

animation
 property to different values based on the internal state, and framer-motion will animate between those values when the state changes:

const Three = () => {
  const [active, setActive] = React.useState(false);

  return (
    <motion.div
      className="rectangle"
      animate={
        active
          ? { background: "#ff00b1", rotate: 90 }
          : { background: "#0D00FF", rotate: 0 }
      }
      onClick={() => setActive(!active)}
    >
      Click me!
    </motion.div>
  );
};
Note that the component re-renders only when state changes, and not on every animation frame, which makes animations very efficient.

Variants

The real power of framer-motion comes from using variants. Let’s start by exploring how we can rewrite the previous example to use variants.

We’ll begin by extracting inline definition of animatable properties from 

animate
 prop into a separate object. This object will contain key-value pairs, where keys are some meaningful names that we give to our animatable properties, and values are the properties themselves. Then we can pass this
variants
object to variants prop, and inside 
animation
 we can toggle animations based on the string names we gave to them:

const Four = () => {
  const [active, setActive] = React.useState(false);
  
  const rectangle: Variants = {
    active: { background: "#ff00b1", rotate: 90 },
    disabled: { background: "#0D00FF", rotate: 0 }
  };

  return (
    <motion.div
      className="rectangle"
      variants={rectangle}
      animate={active ? "active" : "disabled"}
      onClick={() => setActive(!active)}
    >
      Click me!
    </motion.div>
  );
};
This example works, but it’s not very useful. The power of variants is in orchestrating complex animations throughout a component tree, and to see that, we’ll need a slightly bigger example.

In the example below, we have a container 

div
 that has three child 
div
s inside of it. Container 
div
 uses the same 
onClick
 animation that we’ve seen before:

const Five = () => {
  const container: Variants = {
    active: {
      background: "#ff00b1"
    },
    disabled: {
      background: "#0D00FF"
    }
  };

  const [active, setActive] = React.useState(false);

  return (
    <motion.div
      variants={container}
      animate={active ? "active" : "disabled"}
      onClick={() => setActive(!active)}
      className="container"
    >
      {[0, 1, 2].map(value => (
        <div key={value} className="box" />
      ))}
    </motion.div>
  );
};
Now we can animate children elements simultaneously with the parent by setting their own variants object. If the descriptive names of child animations match those of the parent, child animations will be triggered when parent animation is triggered.

Notice how both 

container
 and 
box
 variants have the same keys 
active
and 
disabled
:

const Six = () => {
  const container: Variants = {
    active: {
      background: "#ff00b1",
    },
    disabled: {
      background: "#0D00FF"
    }
  };

  const box: Variants = {
    active: {
      rotate: 90,
      opacity: 1
    },
    disabled: {
      rotate: 0,
      opacity: 0.7
    }
  };

  const [active, setActive] = React.useState(false);

  return (
    <motion.div
      variants={container}
      animate={active ? "active" : "disabled"}
      onClick={() => setActive(!active)}
      className="container"
    >
      {[0, 1, 2].map(value => (
        <motion.div key={value} className="box" variants={box} />
      ))}
    </motion.div>
  );
};

Configuring variants

Variants also allow us to orchestrate the child animations. We can do that by providing 

transition
 property inside the animation object.

For example, we can set 

staggerChildren
 children property, which specifies the delay in seconds between child animations:

const container: Variants = {
  active: {
    background: "#ff00b1",
    transition: {
      staggerChildren: 0.5
    }
  },
  disabled: {
    background: "#0D00FF"
  }
};

Note how transition is applied only when we transition into a given variant. Since we defined 

transition
 property inside 
active
 variant, the stagger animation is only applied when we transition from 
disabled
 into 
active
, but not when we transition from 
active
 to 
disabled
.

By default, variants start animating parent element and its children at the same time. We can control that behavior using 

when
 property. We can set it to 
beforeChildren
 to make parent element animate first, or to 
afterChildren
, to make parent element animate after its children:

const container: Variants = {
  active: {
    background: "#ff00b1",
    transition: {
      staggerChildren: 0.5,
      when: "beforeChildren"
    }
  },
  disabled: {
    background: "#0D00FF"
  }
};

With this configuration, the parent 

div
 changes background color first, and then child elements rotate with a staggered delay.

There are a lot more properties of variants that we can control - animation delays, stagger direction, etc. You can find more information on them in framer-motion .

Wrapping up

In this article, we’ve seen how easy it is to animate React components using declarative API that framer-motion provides. However, we just scratched the surface, since there’s a lot more that framer-motion is capable of - gestures, dragging, working with SVG paths and much more. If you’re interested in learning more -  that will cover all the cool things that framer-motion has to offer.


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