build: optimize the rollup build

- remove babel-runtime
- add babel-dev-expressions
- switch to tiny-invariant

Author: thebuilder

package.json

@@ -7,6 +7,7 @@
   "unpkg": "react-intersection-observer.umd.min.js",
   "typings": "index.d.ts",
   "author": "Daniel Schmidt",
+  "sideEffects": false,
   "repository": {
     "type": "git",
     "url": "https://github.com/thebuilder/react-intersection-observer.git"
@@ -109,7 +110,6 @@
     ]
   },
   "dependencies": {
-    "@babel/runtime": "^7.0.0",
     "invariant": "^2.0.0"
   },
   "peerDependencies": {
@@ -134,14 +134,13 @@
     "@types/jest": "^24.0.18",
     "@types/react": "^16.9.1",
     "@types/react-dom": "^16.9.0",
-    "@types/storybook__addon-actions": "^3.4.1",
-    "@types/storybook__addon-knobs": "^5.0.2",
     "@types/storybook__react": "^4.0.0",
     "@typescript-eslint/eslint-plugin": "^2.0.0",
     "@typescript-eslint/parser": "^2.0.0",
     "babel-eslint": "^10.0.3",
     "babel-jest": "^24.5.0",
     "babel-loader": "^8.0.5",
+    "babel-plugin-dev-expression": "^0.2.2",
     "concurrently": "^5.0.0",
     "coveralls": "^3.0.5",
     "eslint": "^6.2.1",
@@ -166,6 +165,7 @@
     "rollup-plugin-node-resolve": "^5.2.0",
     "rollup-plugin-replace": "^2.1.0",
     "rollup-plugin-terser": "^5.1.1",
+    "tiny-invariant": "^1.0.6",
     "typescript": "^3.5.3"
   }
 }

rollup.config.js

@@ -20,7 +20,7 @@ const getBabelOptions = ({ useESModules }) => ({
   extensions,
   include: ['src/**/*'],
   presets: ['@babel/preset-typescript'],
-  plugins: [['@babel/transform-runtime', { regenerator: false, useESModules }]],
+  plugins: [['babel-plugin-dev-expression']],
 })
 
 export default [

src/InView.tsx

@@ -1,5 +1,5 @@
 import * as React from 'react'
-import invariant from 'invariant'
+import invariant from 'tiny-invariant'
 import { observe, unobserve } from './intersection'
 import { IntersectionObserverProps, PlainChildrenProps } from './index'
 
@@ -39,13 +39,10 @@ export class InView extends React.Component<
   }
 
   componentDidMount() {
-    /* istanbul ignore else  */
-    if (process.env.NODE_ENV !== 'production') {
-      invariant(
-        this.node,
-        `react-intersection-observer: No DOM node found. Make sure you forward "ref" to the root DOM element you want to observe.`,
-      )
-    }
+    invariant(
+      this.node,
+      `react-intersection-observer: No DOM node found. Make sure you forward "ref" to the root DOM element you want to observe.`,
+    )
   }
 
   componentDidUpdate(prevProps: IntersectionObserverProps, prevState: State) {

src/__tests__/Observer.test.js

@@ -3,10 +3,10 @@ import React from 'react'
 import { fireEvent, render } from '@testing-library/react'
 import { observe, unobserve } from '../intersection'
 import Observer from '../'
-import invariant from 'invariant'
+import invariant from 'tiny-invariant'
 
 jest.mock('../intersection')
-jest.mock('invariant')
+jest.mock('tiny-invariant')
 
 const plainChild = ({ ref }) => <div ref={ref} />
 afterEach(() => {

src/intersection.ts

@@ -1,4 +1,4 @@
-import invariant from 'invariant'
+import invariant from 'tiny-invariant'
 import { ObserverInstance, ObserverInstanceCallback } from './index'
 
 const INSTANCE_MAP: Map<Element, ObserverInstance> = new Map()
@@ -41,7 +41,6 @@ export function observe(
   invariant(
     !INSTANCE_MAP.has(element),
     "react-intersection-observer: Trying to observe %s, but it's already being observed by another instance.\nMake sure the `ref` is only used by a single <Observer /> instance.\n\n%s",
-    element,
   )
   /* istanbul ignore if */
   if (!element) return