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