Add TypeScript definitions

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2019 Envato
+Copyright (c) 2019-2021 Envato
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -13,12 +13,12 @@
 
 ---
 
-> Observe multiple React components with a single ResizeObserver.
+> Observe multiple DOM elements with a single ResizeObserver.
 
 This package provides you with:
 
-* a context `<Provider>` with a `ResizeObserver` instance;
-* a `useResizeObserver()` hook to observe any element's changes in size.
+- a context `<Provider>` with a `ResizeObserver` instance;
+- a `useResizeObserver()` hook to observe any element's size changes.
 
 This allows you to know the size of each observed element.
 
@@ -41,14 +41,10 @@ npm install @envato/react-resize-observer-hook
 ```javascript
 import { Provider as ResizeObserverProvider } from '@envato/react-resize-observer-hook';
 
-const App = () => (
-  <ResizeObserverProvider>
-    ...
-  </ResizeObserverProvider>
-);
+const App = () => <ResizeObserverProvider>...</ResizeObserverProvider>;
 ```
 
-⚠️ **Caution** — You may need to pass some props to `<Provider>` to increase browser support. Please refer to the [React Breakpoints API Docs](https://github.com/envato/react-breakpoints/docs/api.md#provider).
+⚠️ **Caution** — You may need to pass some props to `<Provider>` to increase **browser support**. Please refer to the [React Breakpoints API Docs](https://github.com/envato/react-breakpoints/docs/api.md#provider).
 
 ## Observe an element
 
@@ -59,7 +55,11 @@ const ObservedDiv = () => {
   const [ref, observedEntry] = useResizeObserver();
   const { width, height } = observedEntry.contentRect;
 
-  return <div ref={ref}>This element is {width}px wide and {height}px high.</div>
+  return (
+    <div ref={ref}>
+      This element is {width}px wide and {height}px high.
+    </div>
+  );
 };
 ```
 
@@ -71,13 +71,16 @@ const options = {
 };
 
 const [ref, observedEntry] = useResizeObserver(options);
+
+const width = observedEntry.borderBox[0].inlineSize;
+const height = observedEntry.borderBox[0].blockSize;
 ```
 
 See [MDN reference guide](https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver) for further information.
 
 # Maintainers
 
-* [Marc Dingena](https://github.com/mdingena) (owner)
+- [Marc Dingena](https://github.com/mdingena) (owner)
 
 # Contributing
 

package.json

@@ -3,41 +3,50 @@
   "version": "1.0.1",
   "description": "Observe multiple React components with a single ResizeObserver.",
   "main": "dist/index.js",
+  "types": "dist/index.d.ts",
   "scripts": {
-    "build": "babel src/ -d dist/ --source-maps",
+    "build": "tsc -b",
     "prepare": "npm run build"
   },
   "repository": {
     "type": "git",
     "url": "git+https://github.com/envato/react-resize-observer-hook.git"
   },
   "keywords": [
+    "resize-observer",
     "react-hooks",
     "hooks",
     "react",
-    "performance",
-    "resize-observer"
+    "performance"
   ],
-  "author": "Envato",
+  "author": "[email protected]",
   "license": "MIT",
   "bugs": {
     "url": "https://github.com/envato/react-resize-observer-hook/issues"
   },
   "homepage": "https://github.com/envato/react-resize-observer-hook#readme",
   "peerDependencies": {
-    "react": ">=16.8.0",
-    "react-dom": ">=16.8.0"
+    "react": "16.8 - 17",
+    "react-dom": "16.8 - 17"
   },
   "devDependencies": {
-    "@babel/cli": "^7.8.4",
-    "@babel/core": "^7.8.6",
-    "@babel/preset-env": "^7.7.7",
-    "@babel/preset-react": "^7.8.3",
+    "@types/react": "^17.0.0",
+    "@typescript-eslint/eslint-plugin": "^4.13.0",
+    "@typescript-eslint/parser": "^4.13.0",
+    "babel-eslint": "^10.1.0",
+    "eslint": "^7.17.0",
+    "eslint-config-react-app": "^6.0.0",
+    "eslint-plugin-flowtype": "^5.2.0",
+    "eslint-plugin-import": "^2.22.1",
+    "eslint-plugin-jsx-a11y": "^6.4.1",
+    "eslint-plugin-react": "^7.22.0",
+    "eslint-plugin-react-hooks": "^4.2.0",
     "husky": "^4.3.7",
     "lint-staged": "^10.5.3",
     "prettier": "^2.2.1",
     "react": "^17.0.1",
-    "react-dom": "^17.0.1"
+    "react-dom": "^17.0.1",
+    "typescript": "^4.2.2"
   },
   "eslintConfig": {
     "extends": "react-app"

src/Context.ts

@@ -0,0 +1,3 @@
+import { createContext } from 'react';
+
+export const Context = createContext<ResizeObserver | null>(null);

src/ExtendedResizeObserverEntry.ts

@@ -0,0 +1,5 @@
+import { ObservedElement } from './ObservedElement';
+
+export interface ExtendedResizeObserverEntry extends ResizeObserverEntry {
+  target: ObservedElement;
+}

src/ObservedElement.ts

@@ -0,0 +1,5 @@
+import { ExtendedResizeObserverEntry } from './ExtendedResizeObserverEntry';
+
+export interface ObservedElement extends Element {
+  onResizeObservation?: (resizeObserverEntry: ExtendedResizeObserverEntry) => void;
+}

src/Provider.tsx

@@ -0,0 +1,25 @@
+import { createResizeObserver } from './createResizeObserver';
+import { Context } from './Context';
+
+interface ProviderProps {
+  ponyfill?: typeof ResizeObserver;
+  children: React.ReactNode;
+}
+
+/**
+ * See API Docs: {@linkcode https://github.com/envato/react-breakpoints/blob/master/docs/api.md#provider|Provider}
+ *
+ * Returns a React context provider with a ResizeObserver instance as its value.
+ * Uses `window.ResizeObserver` to construct the instance if no `ponyfill` prop is provided.
+ * @example
+ * return (
+ *   <Provider ponyfill={ResizeObserver}>
+ *     ...
+ *   </Provider>
+ * );
+ */
+export const Provider = ({ ponyfill = undefined, children }: ProviderProps) => {
+  const instance = createResizeObserver(ponyfill || window.ResizeObserver);
+
+  return <Context.Provider value={instance}>{children}</Context.Provider>;
+};

src/createResizeObserver.ts

@@ -0,0 +1,22 @@
+import { ExtendedResizeObserverEntry } from './ExtendedResizeObserverEntry';
+
+/**
+ * Creates a new ResizeObserver instance that works with the
+ * {@linkcode https://github.com/envato/react-breakpoints/blob/master/docs/api.md#useresizeobserver|useResizeObserver}
+ * hook.
+ * @example
+ * const resizeObserverInstance = createResizeObserver(window.ResizeObserver);
+ * return (
+ *   <Context.Provider value={resizeObserverInstance}>
+ *     ...
+ *   </Context.Provider>
+ * );
+ */
+export const createResizeObserver = (Constructor: typeof ResizeObserver) => {
+  const handleResizeObserverEntry = (resizeObserverEntry: ExtendedResizeObserverEntry) => {
+    const { onResizeObservation } = resizeObserverEntry.target;
+    onResizeObservation && onResizeObservation(resizeObserverEntry);
+  };
+
+  return new Constructor((entries: ExtendedResizeObserverEntry[]) => entries.forEach(handleResizeObserverEntry));
+};

src/index.ts

@@ -0,0 +1,4 @@
+export { Context } from './Context';
+export { Provider } from './Provider';
+export { createResizeObserver } from './createResizeObserver';
+export { useResizeObserver } from './useResizeObserver';

src/useResizeObserver.ts

@@ -0,0 +1,51 @@
+import { useContext, useCallback, useRef, useState } from 'react';
+import { Context } from './Context';
+import { ObservedElement } from './ObservedElement';
+import { ExtendedResizeObserverEntry } from './ExtendedResizeObserverEntry';
+
+/**
+ * See API Docs: {@linkcode https://github.com/envato/react-breakpoints/blob/master/docs/api.md#useresizeobserver|useResizeObserver}
+ *
+ * Returns a React callback ref to attach to a DOM element. It also returns
+ * a resize observation entry every time the observed element changes size.
+ * This causes the component that uses `useResizeObserver` to rerender.
+ * @example
+ * const [ref, observedEntry] = useResizeObserver(options);
+ * const observedWidth = observedEntry.borderBoxSize[0].inlineSize;
+ * return (
+ *   <div ref={ref}>
+ *     This container is {observedWidth}px wide.
+ *   </div>
+ * );
+ */
+export const useResizeObserver = (
+  options: ResizeObserverOptions = {}
+): [React.RefCallback<ObservedElement | null>, ExtendedResizeObserverEntry | null] => {
+  const resizeObserver = useContext<ResizeObserver | null>(Context);
+
+  const [observedEntry, setObservedEntry] = useState<ExtendedResizeObserverEntry | null>(null);
+
+  const handleResizeObservation = (resizeObserverEntry: ExtendedResizeObserverEntry) =>
+    setObservedEntry(resizeObserverEntry);
+
+  const ref = useRef<ObservedElement | null>(null);
+
+  const setRef = useCallback(
+    node => {
+      if (ref.current) {
+        resizeObserver?.unobserve(ref.current);
+        delete ref.current.onResizeObservation;
+      }
+
+      if (node) {
+        node.onResizeObservation = handleResizeObservation;
+        resizeObserver?.observe(node, options);
+      }
+
+      ref.current = node;
+    },
+    [resizeObserver, options]
+  );
+
+  return [setRef, observedEntry];
+};

tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "compilerOptions": {
+    "target": "es5",
+    "module": "commonjs",
+    "jsx": "react-jsx",
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "outDir": "./dist",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true
+  },
+  "include": ["./src/**/*"]
+}