TypeError: react_1.useEffect is not a function

Question

I am trying to make us of useEffect in my React component but I am encountering an issue with the following error:

TypeError: react_1.useEffect is not a function

and

Uncaught (in promise) TypeError: react_1.useState is not a function

I have imported the libraries like this

import React, { useEffect } from 'react'

and have the useEffect like this:

useEffect(() => {
  console.log("This is cool")
}, [intentButton])

The react version is 16.7.0

"Hooks are a new addition in React 16.8. They let you use state and other React features without writing a class" From React docs. Try using a later version of React and see if it fixed the issue — dEBA M, Sep 17 '21 at 13:28

score 1 · Answer 1 · answered Sep 18 '21 at 00:00

this is because the react V16.7 does not have hooks

The resolution is to downgrade to

   npm i react@next react-dom@next

which as of 2018/12/20 is 16.7.0-alpha.2:

yarn add react@next react-dom@next

then lose the test renderer:

 import React from 'react'
 import ReactDOM from 'react-dom'
 import App from './App'
 it('renders without crashing', () => {
    const div = document.createElement('div')
    ReactDOM.render(<App />, div)
    ReactDOM.unmountComponentAtNode(div)
 })

This is what package.json should be:

  "react": "^16.7.0-alpha.2",
  "react-dom": "^16.7.0-alpha.2",

TypeError: react_1.useEffect is not a function

1 Answers1