Add tests for Theatre.js + popular setups in the ecosystem (#165)

This implements some basic infra for testing Theatre.js with popular setups such as npm/yarn/pnpm, webpack/vite/parcel, js/ts, etc.

So far, the only existing setup has been with create-react-app. Will add more in the future.

Co-authored-by: Fülöp <fulopkovacs@users.noreply.github.com>
Co-authored-by: Aria Minaei <aria.minaei@gmail.com>

ecosystem-tests/README.md

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+# Ecosystem tests
+
+Inspired by the
+[#help channel on our Discord](https://discord.com/channels/870988717190426644/870988717190426647)
+we collect examples for including `Theatre.js` in project that use different
+tools (`parcel`, `Next.js`, `vanilla Rollup`, etc...) to build them in the CI
+(these are the _ecosystem tests_).
+
+## The currently tested setups
+
+| setup                        | tools                               | `package.json`                        |
+| ---------------------------- | ----------------------------------- | ------------------------------------- |
+| ecosystem-tests/create-react-app | `create-react-app`, `r3f extension` | [link](create-react-app/package.json) |
+
+## Testing the configurations locally
+
+```sh
+# clean existing build artifacts
+yarn clean
+# this will build all packages, publish them to yalc, link them to each setup, and run the `yarn build` command on that setup
+yarn test:ecosystem
+```
+
+After running the above, you can also start the dev server of each setup to try it manually:
+
+```sh
+cd ecosystem-tests/[setup-name]
+yarn start
+```
+
+## Adding a new setup
+
+If you wish to test a new setup (say Vite, or cool-new-bundler), here is how to
+do it:
+
+1. Build the monorepo packages and publish them to the local npm registry,
+   [yalc](https://github.com/wclr/yalc).
+
+   ```sh
+   cd /path/to/theatre-monorepo
+   # build all the packages
+   yarn build
+   # publish them to yalc (the local npm registry)
+   zx scripts/publish-to-yalc.mjs
+   ```
+
+1. Start your new setup in a directory outside of the monorepo
+
+   ```sh
+   # start a project outside the monorepo we'll copy it in later
+   cd /path/---------outside---------/theatre-monorepo
+   # make a new setup folder
+   mkdir new-setup .
+   cd new-setup
+   ```
+
+1. Bootstrap your setup using npm, yarn, or other bootstrapping scripts (like
+   `npx create-react-app`)
+
+   ```sh
+   npm init --yes
+   ```
+
+1. Make sure there is a `yarn.lock` or `package-lock.json` file in this
+   directory. Otherwise, when we move it back into the monorepo, yarn will
+   complain that this package is not listed in the monorepo as a workspace.
+
+   ```sh
+   touch yarn.lock
+   ```
+
+1. Copy the new directory back to the monorepo and `cd` into it
+
+   ```sh
+   cp -r ./path/---------outside---------/theatre-monorepo/new-setup /path/to/theatre/monorepo/build-tests/new-setup
+   cd /path/to/theatre/monorepo/build-tests/new-setup
+   ```
+
+1. Let yarn/npm run an install
+
+   ```sh
+   yarn install
+   ```
+
+1. Install `@theatre/core` and `@theatre/studio`, and possibly `@theatre/r3f`
+   from the local registry:
+
+   ```sh
+   npx yalc link @theatre/core @theatre/studio @theatre/r3f
+   ```
+
+1. Copy the source (`src/*`) of one of the other setups into `new-setup` so you
+   don't have to start from scratch.
+
+1. Make sure that you add a `yarn build` script to `new-setup/package.json`,
+   because it
+   [will be used](https://github.com/theatre-js/theatre/blob/db7dadc0c997316f2027736e2ecba0ea4acda2d4/scripts/build-tests/build-setups.mjs#L18)
+   to build the setup in the CI.
+
+1. Test your setup by running its dev server or doing a build
+
+   ```sh
+   yarn start
+   ```
+
+> **Gotchas**
+> Some bundlers like webpack are not configured to work well with yarn workspaces by default. For example, the webpack config of create-react-app, tries to look up the node_modules chain to find missing dependencies, which is not a behavior that we want in build-tests setups. So if a setup doesn't work, try running it outside the monorepo to see if being in the monorepo is what's causing it to fail.
+
+Feel free to check out [the existing setups](#the-currently-tested-setups) in
+`ecosystem-tests` if you get stuck.

ecosystem-tests/create-react-app/.gitignore

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+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.js
+
+# testing
+/coverage
+
+# production
+/build
+
+# misc
+.DS_Store
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*

ecosystem-tests/create-react-app/README.md

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+# Theatre.js project with `create-react-app` using the `r3f extension`
+
+## Setup
+
+Please refer to [this guide](../README.md#testing-the-configurations-locally).
+
+## Usage
+
+- start the development server:
+  ```sh
+  yarn start
+  ```
+- build the project:
+  ```sh
+  yarn build
+  ```

ecosystem-tests/create-react-app/package.json

@@ -0,0 +1,38 @@
+{
+  "name": "@theatre-build-tests/react-app",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "start": "react-scripts start",
+    "build": "react-scripts build",
+    "test": "react-scripts test",
+    "eject": "react-scripts eject"
+  },
+  "dependencies": {
+    "@react-three/drei": "^7.2.2",
+    "@testing-library/jest-dom": "^5.11.4",
+    "@testing-library/react": "^11.1.0",
+    "@testing-library/user-event": "^12.1.10",
+    "react-scripts": "^5.0.1",
+    "three": "^0.130.1",
+    "web-vitals": "^1.0.1"
+  },
+  "eslintConfig": {
+    "extends": [
+      "react-app",
+      "react-app/jest"
+    ]
+  },
+  "browserslist": {
+    "production": [
+      ">0.2%",
+      "not dead",
+      "not op_mini all"
+    ],
+    "development": [
+      "last 1 chrome version",
+      "last 1 firefox version",
+      "last 1 safari version"
+    ]
+  }
+}

ecosystem-tests/create-react-app/public/index.html

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+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <meta name="theme-color" content="#000000" />
+    <meta
+      name="description"
+      content="Web site created using create-react-app"
+    />
+    <link rel="apple-touch-icon" href="%PUBLIC_URL%/logo192.png" />
+    <!--
+      manifest.json provides metadata used when your web app is installed on a
+      user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
+    -->
+    <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
+    <!--
+      Notice the use of %PUBLIC_URL% in the tags above.
+      It will be replaced with the URL of the `public` folder during the build.
+      Only files inside the `public` folder can be referenced from the HTML.
+
+      Unlike "/favicon.ico" or "favicon.ico", "%PUBLIC_URL%/favicon.ico" will
+      work correctly both with client-side routing and a non-root public URL.
+      Learn how to configure a non-root public URL by running `npm run build`.
+    -->
+    <title>React App</title>
+  </head>
+  <body>
+    <noscript>You need to enable JavaScript to run this app.</noscript>
+    <div id="root"></div>
+    <!--
+      This HTML file is a template.
+      If you open it directly in the browser, you will see an empty page.
+
+      You can add webfonts, meta tags, or analytics to this file.
+      The build step will place the bundled scripts into the <body> tag.
+
+      To begin the development, run `npm start` or `yarn start`.
+      To create a production bundle, use `npm run build` or `yarn build`.
+    -->
+  </body>
+</html>

ecosystem-tests/create-react-app/public/manifest.json

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+{
+  "short_name": "React App",
+  "name": "Create React App Sample",
+  "icons": [
+    {
+      "src": "favicon.ico",
+      "sizes": "64x64 32x32 24x24 16x16",
+      "type": "image/x-icon"
+    },
+    {
+      "src": "logo192.png",
+      "type": "image/png",
+      "sizes": "192x192"
+    },
+    {
+      "src": "logo512.png",
+      "type": "image/png",
+      "sizes": "512x512"
+    }
+  ],
+  "start_url": ".",
+  "display": "standalone",
+  "theme_color": "#000000",
+  "background_color": "#ffffff"
+}

ecosystem-tests/create-react-app/public/robots.txt

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+# https://www.robotstxt.org/robotstxt.html
+User-agent: *
+Disallow:

ecosystem-tests/create-react-app/src/App.css

@@ -0,0 +1,38 @@
+.App {
+  text-align: center;
+}
+
+.App-logo {
+  height: 40vmin;
+  pointer-events: none;
+}
+
+@media (prefers-reduced-motion: no-preference) {
+  .App-logo {
+    animation: App-logo-spin infinite 20s linear;
+  }
+}
+
+.App-header {
+  background-color: #282c34;
+  min-height: 100vh;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  font-size: calc(10px + 2vmin);
+  color: white;
+}
+
+.App-link {
+  color: #61dafb;
+}
+
+@keyframes App-logo-spin {
+  from {
+    transform: rotate(0deg);
+  }
+  to {
+    transform: rotate(360deg);
+  }
+}

ecosystem-tests/create-react-app/src/App.js

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+import {getProject} from '@theatre/core'
+import * as THREE from 'three'
+import {useState, useEffect, useRef} from 'react'
+import {useFrame, Canvas} from '@react-three/fiber'
+import {Shadow, softShadows} from '@react-three/drei'
+import React from 'react'
+import studio from '@theatre/studio'
+import {editable as e, SheetProvider, extension} from '@theatre/r3f'
+
+if (process.env.NODE_ENV === 'development') {
+  studio.extend(extension)
+  studio.initialize()
+}
+
+// Soft shadows are expensive, comment and refresh when it's too slow
+softShadows()
+
+// credit: https://codesandbox.io/s/camera-pan-nsb7f
+
+function Button() {
+  const vec = new THREE.Vector3()
+  const light = useRef(undefined)
+  const [active, setActive] = useState(false)
+  const [zoom, set] = useState(true)
+  useEffect(
+    () => void (document.body.style.cursor = active ? 'pointer' : 'auto'),
+    [active],
+  )
+
+  useFrame((state) => {
+    const step = 0.1
+    const camera = state.camera
+    camera.fov = THREE.MathUtils.lerp(camera.fov, zoom ? 10 : 42, step)
+    camera.position.lerp(
+      vec.set(zoom ? 25 : 10, zoom ? 1 : 5, zoom ? 0 : 10),
+      step,
+    )
+    state.camera.lookAt(0, 0, 0)
+    state.camera.updateProjectionMatrix()
+
+    light.current.position.lerp(
+      vec.set(zoom ? 4 : 0, zoom ? 3 : 8, zoom ? 3 : 5),
+      step,
+    )
+  })
+
+  return (
+    <e.mesh
+      receiveShadow
+      castShadow
+      onClick={() => set(!zoom)}
+      onPointerOver={() => setActive(true)}
+      onPointerOut={() => setActive(false)}
+      uniqueName="The Button"
+    >
+      <sphereBufferGeometry args={[0.75, 64, 64]} />
+      <meshPhysicalMaterial
+        color={active ? 'purple' : '#e7b056'}
+        clearcoat={1}
+        clearcoatRoughness={0}
+      />
+      <Shadow
+        position-y={-0.79}
+        rotation-x={-Math.PI / 2}
+        opacity={0.6}
+        scale={[0.8, 0.8, 1]}
+      />
+      <directionalLight
+        ref={light}
+        castShadow
+        intensity={1.5}
+        shadow-camera-far={70}
+      />
+    </e.mesh>
+  )
+}
+
+function Plane({color, uniqueName, ...props}) {
+  return (
+    <e.mesh receiveShadow castShadow {...props} uniqueName={uniqueName}>
+      <boxBufferGeometry />
+      <meshStandardMaterial color={color} />
+    </e.mesh>
+  )
+}
+
+const sheet = getProject('Playground - R3F').sheet('R3F-Canvas')
+
+function App() {
+  return (
+    <div>
+      <Canvas
+        // @ts-ignore
+        shadowMap
+      >
+        <SheetProvider sheet={sheet}>
+          {/* @ts-ignore */}
+          <e.perspectiveCamera makeDefault uniqueName="Camera" />
+          <ambientLight intensity={0.4} />
+          <e.pointLight
+            position={[-10, -10, 5]}
+            intensity={2}
+            color="#ff20f0"
+            uniqueName="Light 1"
+          />
+          <e.pointLight
+            position={[0, 0.5, -1]}
+            distance={1}
+            intensity={2}
+            color="#e4be00"
+            uniqueName="Light 2"
+          />
+          <group position={[0, -0.9, -3]}>
+            <Plane
+              color="hotpink"
+              rotation-x={-Math.PI / 2}
+              position-z={2}
+              scale={[4, 20, 0.2]}
+              uniqueName="plane1"
+            />
+            <Plane
+              color="#e4be00"
+              rotation-x={-Math.PI / 2}
+              position-y={1}
+              scale={[4.2, 0.2, 4]}
+              uniqueName="plane2"
+            />
+            <Plane
+              color="#736fbd"
+              rotation-x={-Math.PI / 2}
+              position={[-1.7, 1, 3.5]}
+              scale={[0.5, 4, 4]}
+              uniqueName="plane3"
+            />
+            <Plane
+              color="white"
+              rotation-x={-Math.PI / 2}
+              position={[0, 4.5, 3]}
+              scale={[2, 0.03, 4]}
+              uniqueName="plane4"
+            />
+          </group>
+          <Button />
+        </SheetProvider>
+      </Canvas>
+    </div>
+  )
+}
+
+export default App

ecosystem-tests/create-react-app/src/App.test.js

@@ -0,0 +1,7 @@
+import {render, screen} from '@testing-library/react'
+
+test('renders learn react link', () => {
+  render(<App />)
+  const linkElement = screen.getByText(/learn react/i)
+  expect(linkElement).toBeInTheDocument()
+})

ecosystem-tests/create-react-app/src/index.css

@@ -0,0 +1,13 @@
+body {
+  margin: 0;
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
+    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
+    sans-serif;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+}
+
+code {
+  font-family: source-code-pro, Menlo, Monaco, Consolas, 'Courier New',
+    monospace;
+}

ecosystem-tests/create-react-app/src/index.js

@@ -0,0 +1,19 @@
+import ReactDOM from 'react-dom'
+import './index.css'
+import reportWebVitals from './reportWebVitals'
+import '@theatre/studio'
+import {getProject} from '@theatre/core'
+import React from 'react'
+import App from './App'
+
+ReactDOM.render(
+  <React.StrictMode>
+    <App project={getProject('CRA project')} />
+  </React.StrictMode>,
+  document.getElementById('root'),
+)
+
+// If you want to start measuring performance in your app, pass a function
+// to log results (for example: reportWebVitals(console.log))
+// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals
+reportWebVitals()

ecosystem-tests/create-react-app/src/logo.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 841.9 595.3"><g fill="#61DAFB"><path d="M666.3 296.5c0-32.5-40.7-63.3-103.1-82.4 14.4-63.6 8-114.2-20.2-130.4-6.5-3.8-14.1-5.6-22.4-5.6v22.3c4.6 0 8.3.9 11.4 2.6 13.6 7.8 19.5 37.5 14.9 75.7-1.1 9.4-2.9 19.3-5.1 29.4-19.6-4.8-41-8.5-63.5-10.9-13.5-18.5-27.5-35.3-41.6-50 32.6-30.3 63.2-46.9 84-46.9V78c-27.5 0-63.5 19.6-99.9 53.6-36.4-33.8-72.4-53.2-99.9-53.2v22.3c20.7 0 51.4 16.5 84 46.6-14 14.7-28 31.4-41.3 49.9-22.6 2.4-44 6.1-63.6 11-2.3-10-4-19.7-5.2-29-4.7-38.2 1.1-67.9 14.6-75.8 3-1.8 6.9-2.6 11.5-2.6V78.5c-8.4 0-16 1.8-22.6 5.6-28.1 16.2-34.4 66.7-19.9 130.1-62.2 19.2-102.7 49.9-102.7 82.3 0 32.5 40.7 63.3 103.1 82.4-14.4 63.6-8 114.2 20.2 130.4 6.5 3.8 14.1 5.6 22.5 5.6 27.5 0 63.5-19.6 99.9-53.6 36.4 33.8 72.4 53.2 99.9 53.2 8.4 0 16-1.8 22.6-5.6 28.1-16.2 34.4-66.7 19.9-130.1 62-19.1 102.5-49.9 102.5-82.3zm-130.2-66.7c-3.7 12.9-8.3 26.2-13.5 39.5-4.1-8-8.4-16-13.1-24-4.6-8-9.5-15.8-14.4-23.4 14.2 2.1 27.9 4.7 41 7.9zm-45.8 106.5c-7.8 13.5-15.8 26.3-24.1 38.2-14.9 1.3-30 2-45.2 2-15.1 0-30.2-.7-45-1.9-8.3-11.9-16.4-24.6-24.2-38-7.6-13.1-14.5-26.4-20.8-39.8 6.2-13.4 13.2-26.8 20.7-39.9 7.8-13.5 15.8-26.3 24.1-38.2 14.9-1.3 30-2 45.2-2 15.1 0 30.2.7 45 1.9 8.3 11.9 16.4 24.6 24.2 38 7.6 13.1 14.5 26.4 20.8 39.8-6.3 13.4-13.2 26.8-20.7 39.9zm32.3-13c5.4 13.4 10 26.8 13.8 39.8-13.1 3.2-26.9 5.9-41.2 8 4.9-7.7 9.8-15.6 14.4-23.7 4.6-8 8.9-16.1 13-24.1zM421.2 430c-9.3-9.6-18.6-20.3-27.8-32 9 .4 18.2.7 27.5.7 9.4 0 18.7-.2 27.8-.7-9 11.7-18.3 22.4-27.5 32zm-74.4-58.9c-14.2-2.1-27.9-4.7-41-7.9 3.7-12.9 8.3-26.2 13.5-39.5 4.1 8 8.4 16 13.1 24 4.7 8 9.5 15.8 14.4 23.4zM420.7 163c9.3 9.6 18.6 20.3 27.8 32-9-.4-18.2-.7-27.5-.7-9.4 0-18.7.2-27.8.7 9-11.7 18.3-22.4 27.5-32zm-74 58.9c-4.9 7.7-9.8 15.6-14.4 23.7-4.6 8-8.9 16-13 24-5.4-13.4-10-26.8-13.8-39.8 13.1-3.1 26.9-5.8 41.2-7.9zm-90.5 125.2c-35.4-15.1-58.3-34.9-58.3-50.6 0-15.7 22.9-35.6 58.3-50.6 8.6-3.7 18-7 27.7-10.1 5.7 19.6 13.2 40 22.5 60.9-9.2 20.8-16.6 41.1-22.2 60.6-9.9-3.1-19.3-6.5-28-10.2zM310 490c-13.6-7.8-19.5-37.5-14.9-75.7 1.1-9.4 2.9-19.3 5.1-29.4 19.6 4.8 41 8.5 63.5 10.9 13.5 18.5 27.5 35.3 41.6 50-32.6 30.3-63.2 46.9-84 46.9-4.5-.1-8.3-1-11.3-2.7zm237.2-76.2c4.7 38.2-1.1 67.9-14.6 75.8-3 1.8-6.9 2.6-11.5 2.6-20.7 0-51.4-16.5-84-46.6 14-14.7 28-31.4 41.3-49.9 22.6-2.4 44-6.1 63.6-11 2.3 10.1 4.1 19.8 5.2 29.1zm38.5-66.7c-8.6 3.7-18 7-27.7 10.1-5.7-19.6-13.2-40-22.5-60.9 9.2-20.8 16.6-41.1 22.2-60.6 9.9 3.1 19.3 6.5 28.1 10.2 35.4 15.1 58.3 34.9 58.3 50.6-.1 15.7-23 35.6-58.4 50.6zM320.8 78.4z"/><circle cx="420.9" cy="296.5" r="45.7"/><path d="M520.5 78.1z"/></g></svg>

ecosystem-tests/create-react-app/src/react-app-env.d.ts

@@ -0,0 +1 @@
+/// <reference types="react-scripts" />

ecosystem-tests/create-react-app/src/reportWebVitals.js

@@ -0,0 +1,13 @@
+const reportWebVitals = (onPerfEntry) => {
+  if (onPerfEntry && onPerfEntry instanceof Function) {
+    import('web-vitals').then(({getCLS, getFID, getFCP, getLCP, getTTFB}) => {
+      getCLS(onPerfEntry)
+      getFID(onPerfEntry)
+      getFCP(onPerfEntry)
+      getLCP(onPerfEntry)
+      getTTFB(onPerfEntry)
+    })
+  }
+}
+
+export default reportWebVitals

ecosystem-tests/create-react-app/src/setupTests.js

@@ -0,0 +1,5 @@
+// jest-dom adds custom jest matchers for asserting on DOM nodes.
+// allows you to do things like:
+// expect(element).toHaveTextContent(/react/i)
+// learn more: https://github.com/testing-library/jest-dom
+import '@testing-library/jest-dom'

ecosystem-tests/create-react-app/src/useDrag.js

@@ -0,0 +1,130 @@
+import {useLayoutEffect, useRef} from 'react'
+
+const noop = () => {}
+
+function createCursorLock(cursor) {
+  const el = document.createElement('div')
+  el.style.cssText = `
+    position: fixed;
+    top: 0;
+    right: 0;
+    bottom: 0;
+    left: 0;
+    z-index: 9999999;`
+
+  el.style.cursor = cursor
+  document.body.appendChild(el)
+  const relinquish = () => {
+    document.body.removeChild(el)
+  }
+
+  return relinquish
+}
+
+export default function useDrag(target, opts) {
+  const optsRef = useRef(opts)
+  optsRef.current = opts
+
+  const modeRef = useRef('notDragging')
+
+  const stateRef = useRef({dragHappened: false, startPos: {x: 0, y: 0}})
+
+  useLayoutEffect(() => {
+    if (!target) return
+
+    const getDistances = (event) => {
+      const {startPos} = stateRef.current
+      return [event.screenX - startPos.x, event.screenY - startPos.y]
+    }
+
+    let relinquishCursorLock = noop
+
+    const dragHandler = (event) => {
+      if (!stateRef.current.dragHappened && optsRef.current.lockCursorTo) {
+        relinquishCursorLock = createCursorLock(optsRef.current.lockCursorTo)
+      }
+      if (!stateRef.current.dragHappened) stateRef.current.dragHappened = true
+      modeRef.current = 'dragging'
+
+      const deltas = getDistances(event)
+      optsRef.current.onDrag(deltas[0], deltas[1], event)
+    }
+
+    const dragEndHandler = () => {
+      removeDragListeners()
+      modeRef.current = 'notDragging'
+
+      optsRef.current.onDragEnd &&
+        optsRef.current.onDragEnd(stateRef.current.dragHappened)
+      relinquishCursorLock()
+      relinquishCursorLock = noop
+    }
+
+    const addDragListeners = () => {
+      document.addEventListener('mousemove', dragHandler)
+      document.addEventListener('mouseup', dragEndHandler)
+    }
+
+    const removeDragListeners = () => {
+      document.removeEventListener('mousemove', dragHandler)
+      document.removeEventListener('mouseup', dragEndHandler)
+    }
+
+    const preventUnwantedClick = (event) => {
+      if (optsRef.current.disabled) return
+      if (stateRef.current.dragHappened) {
+        if (
+          !optsRef.current.dontBlockMouseDown &&
+          modeRef.current !== 'notDragging'
+        ) {
+          event.stopPropagation()
+          event.preventDefault()
+        }
+        stateRef.current.dragHappened = false
+      }
+    }
+
+    const dragStartHandler = (event) => {
+      const opts = optsRef.current
+      if (opts.disabled === true) return
+
+      if (event.button !== 0) return
+      const resultOfStart = opts.onDragStart && opts.onDragStart(event)
+
+      if (resultOfStart === false) return
+
+      if (!opts.dontBlockMouseDown) {
+        event.stopPropagation()
+        event.preventDefault()
+      }
+
+      modeRef.current = 'dragStartCalled'
+
+      const {screenX, screenY} = event
+      stateRef.current.startPos = {x: screenX, y: screenY}
+      stateRef.current.dragHappened = false
+
+      addDragListeners()
+    }
+
+    const onMouseDown = (e) => {
+      dragStartHandler(e)
+    }
+
+    target.addEventListener('mousedown', onMouseDown)
+    target.addEventListener('click', preventUnwantedClick)
+
+    return () => {
+      removeDragListeners()
+      target.removeEventListener('mousedown', onMouseDown)
+      target.removeEventListener('click', preventUnwantedClick)
+      relinquishCursorLock()
+
+      if (modeRef.current !== 'notDragging') {
+        optsRef.current.onDragEnd &&
+          optsRef.current.onDragEnd(modeRef.current === 'dragging')
+      }
+      modeRef.current = 'notDragging'
+    }
+  }, [target])
+}