react-is

This package allows you to test arbitrary values and see if they're a particular React element type.

Installation

1# Yarn
2yarn add react-is
3
4# NPM
5npm install react-is

Usage

Determining if a Component is Valid

1import React from "react";
2import * as ReactIs from "react-is";
3
4class ClassComponent extends React.Component {
5  render() {
6    return React.createElement("div");
7  }
8}
9
10const FunctionComponent = () => React.createElement("div");
11
12const ForwardRefComponent = React.forwardRef((props, ref) =>
13  React.createElement(Component, { forwardedRef: ref, ...props })
14);
15
16const Context = React.createContext(false);
17
18ReactIs.isValidElementType("div"); // true
19ReactIs.isValidElementType(ClassComponent); // true
20ReactIs.isValidElementType(FunctionComponent); // true
21ReactIs.isValidElementType(ForwardRefComponent); // true
22ReactIs.isValidElementType(Context.Provider); // true
23ReactIs.isValidElementType(Context.Consumer); // true

Determining an Element's Type

Context

1import React from "react";
2import * as ReactIs from 'react-is';
3
4const ThemeContext = React.createContext("blue");
5
6ReactIs.isContextConsumer(<ThemeContext.Consumer />); // true
7ReactIs.isContextProvider(<ThemeContext.Provider />); // true
8ReactIs.typeOf(<ThemeContext.Provider />) === ReactIs.ContextProvider; // true
9ReactIs.typeOf(<ThemeContext.Consumer />) === ReactIs.ContextConsumer; // true

Element

1import React from "react";
2import * as ReactIs from 'react-is';
3
4ReactIs.isElement(<div />); // true
5ReactIs.typeOf(<div />) === ReactIs.Element; // true

Fragment

1import React from "react";
2import * as ReactIs from 'react-is';
3
4ReactIs.isFragment(<></>); // true
5ReactIs.typeOf(<></>) === ReactIs.Fragment; // true

Portal

1import React from "react";
2import ReactDOM from "react-dom";
3import * as ReactIs from 'react-is';
4
5const div = document.createElement("div");
6const portal = ReactDOM.createPortal(<div />, div);
7
8ReactIs.isPortal(portal); // true
9ReactIs.typeOf(portal) === ReactIs.Portal; // true

StrictMode

1import React from "react";
2import * as ReactIs from 'react-is';
3
4ReactIs.isStrictMode(<React.StrictMode />); // true
5ReactIs.typeOf(<React.StrictMode />) === ReactIs.StrictMode; // true