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| 1 | +# `react-is` |
| 2 | + |
| 3 | +**NOTE:** This README is copied directly from React upstream. |
| 4 | + |
| 5 | +This package allows you to test arbitrary values and see if they're a particular React element type. |
| 6 | + |
| 7 | +## Installation |
| 8 | + |
| 9 | +```sh |
| 10 | +# Yarn |
| 11 | +yarn add react-is |
| 12 | + |
| 13 | +# NPM |
| 14 | +npm install react-is |
| 15 | +``` |
| 16 | + |
| 17 | +## Usage |
| 18 | + |
| 19 | +### Determining if a Component is Valid |
| 20 | + |
| 21 | +```js |
| 22 | +import React from "react"; |
| 23 | +import * as ReactIs from "react-is"; |
| 24 | + |
| 25 | +class ClassComponent extends React.Component { |
| 26 | + render() { |
| 27 | + return React.createElement("div"); |
| 28 | + } |
| 29 | +} |
| 30 | + |
| 31 | +const FunctionComponent = () => React.createElement("div"); |
| 32 | + |
| 33 | +const ForwardRefComponent = React.forwardRef((props, ref) => |
| 34 | + React.createElement(Component, { forwardedRef: ref, ...props }) |
| 35 | +); |
| 36 | + |
| 37 | +const Context = React.createContext(false); |
| 38 | + |
| 39 | +ReactIs.isValidElementType("div"); // true |
| 40 | +ReactIs.isValidElementType(ClassComponent); // true |
| 41 | +ReactIs.isValidElementType(FunctionComponent); // true |
| 42 | +ReactIs.isValidElementType(ForwardRefComponent); // true |
| 43 | +ReactIs.isValidElementType(Context.Provider); // true |
| 44 | +ReactIs.isValidElementType(Context.Consumer); // true |
| 45 | +ReactIs.isValidElementType(React.createFactory("div")); // true |
| 46 | +``` |
| 47 | + |
| 48 | +### Determining an Element's Type |
| 49 | + |
| 50 | +#### Context |
| 51 | + |
| 52 | +```js |
| 53 | +import React from "react"; |
| 54 | +import * as ReactIs from 'react-is'; |
| 55 | + |
| 56 | +const ThemeContext = React.createContext("blue"); |
| 57 | + |
| 58 | +ReactIs.isContextConsumer(<ThemeContext.Consumer />); // true |
| 59 | +ReactIs.isContextProvider(<ThemeContext.Provider />); // true |
| 60 | +ReactIs.typeOf(<ThemeContext.Provider />) === ReactIs.ContextProvider; // true |
| 61 | +ReactIs.typeOf(<ThemeContext.Consumer />) === ReactIs.ContextConsumer; // true |
| 62 | +``` |
| 63 | + |
| 64 | +#### Element |
| 65 | + |
| 66 | +```js |
| 67 | +import React from "react"; |
| 68 | +import * as ReactIs from 'react-is'; |
| 69 | + |
| 70 | +ReactIs.isElement(<div />); // true |
| 71 | +ReactIs.typeOf(<div />) === ReactIs.Element; // true |
| 72 | +``` |
| 73 | + |
| 74 | +#### Fragment |
| 75 | + |
| 76 | +```js |
| 77 | +import React from "react"; |
| 78 | +import * as ReactIs from 'react-is'; |
| 79 | + |
| 80 | +ReactIs.isFragment(<></>); // true |
| 81 | +ReactIs.typeOf(<></>) === ReactIs.Fragment; // true |
| 82 | +``` |
| 83 | + |
| 84 | +#### Portal |
| 85 | + |
| 86 | +```js |
| 87 | +import React from "react"; |
| 88 | +import ReactDOM from "react-dom"; |
| 89 | +import * as ReactIs from 'react-is'; |
| 90 | + |
| 91 | +const div = document.createElement("div"); |
| 92 | +const portal = ReactDOM.createPortal(<div />, div); |
| 93 | + |
| 94 | +ReactIs.isPortal(portal); // true |
| 95 | +ReactIs.typeOf(portal) === ReactIs.Portal; // true |
| 96 | +``` |
| 97 | + |
| 98 | +#### StrictMode |
| 99 | + |
| 100 | +```js |
| 101 | +import React from "react"; |
| 102 | +import * as ReactIs from 'react-is'; |
| 103 | + |
| 104 | +ReactIs.isStrictMode(<React.StrictMode />); // true |
| 105 | +ReactIs.typeOf(<React.StrictMode />) === ReactIs.StrictMode; // true |
| 106 | +``` |
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