Is React
Determine if a variable or expression is a valid element or component in React
A library to determine if a variable or an expression is a React element or component. For a more thorough understanding, this article describes elements and components in React, and this article gives an understanding of the JSX syntax.
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Install
yarn add is-react or npm i --save is-react to use the package.
Examples
Real world:
import React from 'react';
import isReact from 'is-react';
const MyImageComponent = ({ SomeProp }) => {
if (typeof SomeProp === 'string') {
// assume it's the src for an image
return <img src={SomeProp} />;
} else if (isReact.component(SomeProp)) {
return <SomeProp />;
} else if (isReact.element(SomeProp)) {
return SomeProp;
}
return null;
};Samples:
// Class Component
class Foo extends React.Component {
render() {
return <h1>Hello</h1>;
}
}
const foo = <Foo />;
//Functional Component
function Bar(props) {
return <h1>World</h1>;
}
const bar = <Bar />;
// React Element
const header = <h1>Title</h1>;
// Check
isReact.compatible(Foo); // true
isReact.component(Foo); // true
isReact.classComponent(Foo); // true
isReact.functionComponent(Foo); // false
isReact.element(Foo); // false
isReact.compatible(<Foo />); // true
isReact.component(<Foo />); // false
isReact.element(<Foo />); // true
isReact.DOMTypeElement(<Foo />); // false
isReact.compositeTypeElement(<Foo />); // true
isReact.compatible(Bar); // true
isReact.component(Bar); // true
isReact.classComponent(Bar); // false
isReact.functionComponent(Bar); // true
isReact.element(Bar); // false
isReact.compatible(<Bar />); // true
isReact.component(<Bar />); // false
isReact.element(<Bar />); // true
isReact.DOMTypeElement(<Bar />); // false
isReact.compositeTypeElement(<Bar />); // true
isReact.compatible(header); // true
isReact.component(header); // false
isReact.element(header); // true
isReact.DOMTypeElement(header); // true
isReact.compositeTypeElement(header); // falseAPI
import isReact from 'is-react' to use the package
All functions return a boolean. The primary functions you will most likely
use are compatible(), element(), and component().
isReact.compatible()
Determine if a variable or expression is compatible with React. Valid React
components and elements return true.
isReact.element()
Determine if a variable or expression is a React element. Will return true
for both DOM type and Composite type components.
isReact.component()
Determine if a variable or expression is a React component. Will return true
for both functional and class components.
isReact.classComponent()
Determine if a variable or expression is a React class component.
isReact.functionComponent()
Determine if a variable or expression is a React functional component.
isReact.DOMTypeElement()
Determine if a variable or expression is a React DOM type element.
isReact.compositeTypeElement()
Determine if a variable or expression is a React Composite type element.
Thanks!
Inspired by this Stackoverflow answer
