React Flip Primitives

Installation

npm install react-flip-primitives

Usage

Here's a simple and a more complex example

import FlipGroup from "react-flip-primitives";

<FlipGroup changeKey={isActive}>
  {registerNode => (
    <div>
      <div ref={registerNode("text")} style={{height: isActive ? "auto" : 0}}>
        Text
      </div>
      <button ref={registerNode("button")} onClick={toggle}>
        Toggle
      </button>
    </div>
  )}
</FlipGroup>;

import FlipGroup from "react-flip-primitives";

<FlipGroup changeKey={isActive} keysAndData={users.map(u => ({key: u.id, data: u}))}>
  {(registerNode, keysAndData) => (
    <div>
      {keysAndData.map(kd => (
        <Avatar
          key={kd.key}
          user={kd.data}
          ref={registerNode(kd.key, {
            enterPosition: {transform: "translate(0, -20px)"},
            leavePosition: {transform: "translate(0, 20px)"},
            onPresence: presence => ({opacity: presence}),
          })}
        />
      ))}
      <button ref={registerNode("button")}>Add</button>
    </div>
  )}
</FlipGroup>;

Features

• Follows the advice outlined in this google developer post.
• All transitions are based on spring-physics.
• Allow enter and leave animations inspired by react-motion's TransitionMotion.
• Fairly small. Including all its dependencies it weighs in at ~9KB minifed or ~3KB gzipped.
• Doesn't animate size changes (yet), only focusses on position changes.
• Minimizes layout thrashing by batching all layout read and write operations.

Api

FlipGroup

The FlipGroup manages all nodes that are affected by a specific state change. The state change needs to be incorporated into a changeKey to notify the FlipGroup that it should check the registered node's position before the update is applied and after. If the identity of the changeKey changes, getSnapshotBeforeUpdate is called measuring all present flip nodes, and applying smooth transitions to get to the positions determined by componentDidUpdate. (Trivia: since there's no React hook for getSnapshotBeforeUpdate yet, this library still relies on an old school class component).

Props

• changeKey={any}

  Required. Whenever this key changes, it'll check the position of all connected nodes before the DOM update, and after and will perform the necessary transitions.

• keysAndData={{key, data}[]}

  This prop expects an array of {key, data} pairs that are currently available. Once a new key is entered, it will perform an enter transition. Once a key is not present anymore, this key will perform a leave transition.

• children={(registerNode, presentKeysAndData) => ReactNode}

  FlipGroup's uses a render prop to register all nodes that are affected when the changeKey is changed. If you're using enter and leave transitions, you need to use the keys and data provided by presentKeysAndData. This array of {key, data} objects contains all the currently visible keys and will differ from the keysAndData you passed in as a prop if a node is in the process of leaving.

FlipGroup's registerNode(key, opts)

• key

  A key for the node that is unique within it's FlipGroup

• opts.enterPosition={style}

  typically something like {enterPosition: {transform: 'translate(-10,0) scale(0.5)'}}. Note that the passed style object should only contain styles affecting the position of the element. For styling e.g. position, use the onPresence callback

• opts.leavePosition={style}

  typically something like {enterPosition: {transform: 'translate(-10,0) scale(0.5)'}}. Note that the passed style object should only contain styles affecting the position of the element. For styling e.g. position, use the onPresence callback

• opts.positionSpringConfig={...springConfig, noPointerEvents: boolean} defaults to {mass: 1, tension: 170, friction: 26, precision: 0.1, noPointerEvents: false}

  Setting noPointerEvents to true will set pointer-events: none to a node whose position is currently animated.

• opts.onPresence={(presence) => style}

  typically something like (val) => ({opacity: val}). val will be 0 when entering and will target 1 via spring physics. When leaving, val will target 0.

• opts.presenceSpringConfig={springConfig} defaults to {mass: 1, tension: 170, friction: 26, precision: 0.1}

• opts.parentFlipKey={string}

  Cancels out a parent's transforms. If the current node lies within another registerNode we need to notify the FlipGroup that the parent's transforms need to be considered as well.