I have a React app created with create-react-app.
I'm trying to make a custom hook using Microsoft Authentication Library (MSAL). MSAL has a custom React hook that I want to call from my own custom hook.
When I use a hook (any hook) inside my custom hook in a separate file I get this in the browser:
Warning: Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for one of the following reasons:
1. You might have mismatching versions of React and the renderer (such as React DOM)
2. You might be breaking the Rules of Hooks
3. You might have more than one copy of React in the same app
// ourhook/index.ts
import { useEffect } from "react";
export const useMsal2 = () => {
useEffect(() => {
console.log("Hello from our hook!");
});
};
// app.tsx
import React from "react";
import { useMsal2 } from "./ourhook";
const App = () => {
useMsal2();
return <div>App</div>;
};
export default App;
If I call
const { instance } = useMsal();
directly from App.tsx everything works fine. It only appears to be a problem if my custom hook is in its own file.
From what I see I'm not violating any hook rules. I'm calling a hook that's calling a hook, and the first call is from a top level component.
I have read other threads here about hooks in hooks, but none of them has an answer that fits this problem.
Have I missed something about hook rules, or what might be causing this?
Okay, I forgot that we tried to have /ourhook as a freestanding project and then copy pasted it into a create react app app.
Some of you were right, it did have its own version of react.
I'm just going to hide under a rock for the rest of the week.
Thanks for all your help! <3
Try to add this comment just above:
import { useMsal } from "#azure/msal-react";
export const useMsal2 = () => {
// eslint-disable-next-line react-hooks/rules-of-hooks
const { instance } = useMsal();
const request = "";
return {
loginRedirect: () => console.log(""),
}
};
I don't know what useMsal looks like, but from what I see, you don't actually violate any hook rule.
Related
I have a custom hook:
const useMyHook = () => {
const [state, setState] = useState();
...
return state;
};
When I use this hook within the same project it's working fine:
const MyComp = () => {
const state = useMyHook();
...
return <ChildComp {...state} />
}
But when I export this hook from an external package (that I created):
import {useMyHook} from 'my-package';
const MyComp = () => {
const state = useMyHook();
...
return <ChildComp {...state} />
}
I get TypeError: null is not an object (evaluating 'dispatcher.useState') with the following general error:
Warning: Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for one of the following reasons:
1. You might have mismatching versions of React and the renderer (such as React DOM)
2. You might be breaking the Rules of Hooks
3. You might have more than one copy of React in the same app
I want to assume that the problem is not the custom hook since it's working initially. I tought maybe it has to do something with versioning so in the external package I define the package.json with:
"peerDependencies": {
"react": "18.1.0"
},
Same version as the react dependency in my original project in order to resolve react duplication as the error says.
Nothing of the solutions in the web works for me. Any idea what can cause this behavior?
FYI: I'm using react-native (with Expo).
Trying out Next.js but I'm struggling with the following. Just tried to install react-hook-mousetrap and imported it like I normally would:
import useMousetrap from "react-hook-mousetrap";
This gives me the following error:
SyntaxError: Cannot use import statement outside a module
1 > module.exports = require("react-hook-mousetrap");
I am not sure what this means? I then thought it might be a problem with Nextjs's SSR, since my library enables hotkeys and will use some browser APIs. If you already know that I am on the wrong track here you can stop reading now.
What I did next however was this, I tried dynamic imports:
1. Dynamic import with next/dynamic
First thing I came across was next/dynamic, but this seems to be for JSX / React Components only (correct me if I'm wrong). Here I will be importing and using a React hook.
2. Dynamic import with await (...).default
So I tried dynamically importing it as a module, but I'm not sure how to do this exactly.
I need to use my hook at the top level of my component, can't make that Component async and now don't know what to do?
const MyComponent = () => {
// (1) TRIED THIS:
const useMousetrap = await import("react-hook-mousetrap").default;
//can't use the hook here since my Component is not async; Can't make the Component async, since this breaks stuff
// (2) TRIED THIS:
(async () => {
const useMousetrap = (await import("react-hook-mousetrap")).default;
// in this async function i can't use the hook, because it needs to be called at the top level.
})()
//....
}
Any advice here would be appreciated!
The error occurs because react-hook-mousetrap is exported as an ESM library. You can have Next.js transpile it using next-transpile-modules in your next.config.js.
const withTM = require('next-transpile-modules')(['react-hook-mousetrap']);
module.exports = withTM({ /* Your Next.js config */});
I don't know if my answer is actual, but i'm facing whith this problem today, and what that i done:
//test component for modal
const Button: React.FC<{close?: () => void}> = ({ close }) => (
<React.Fragment>
<button type="button" onClick={ close }>Close</button>
</React.Fragment>
);
// async call import react custom hook in next js whithout a dynamic
//import
let newHook;
(async () => {
const { hookFromNodeModules } =
await import('path/to/hook');
newHook = hookFromNodeModules;
})();
export default function Home() {
// check if hook is available
const openModal = newHook && newHook();
const { t } = useTranslation('common');
// useCallback for update call function when hook is available
const handleOpen = React.useCallback(() => {
openModal?.openModal(Button, {});
}, [openModal]);
return ( ...your code )
}
hope this help!)
screen from next.js app
I have a NextJS app. I want to add a function that can redirect to any page using nextjs routing.
For example, after finishing signup I want to redirect to a certain page.
If I create this function (reusable everywhere) :
import { useRouter } from 'next/router'
const goTo = (href) => {
const router = useRouter()
router.push(href)
}
I want to add this to my signup Logic, the problem is that I break React Hooks rules :
react-dom.development.js?ac89:14906 Uncaught (in promise) Error: Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for one of the following reasons:
You might have mismatching versions of React and the renderer (such as React DOM)
You might be breaking the Rules of Hooks
You might have more than one copy of React in the same app
See https://reactjs.org/link/invalid-hook-call for tips about how to debug and fix this problem.
And effectively useRouter is a React Hook, and I'm trying to call it outside a React function, as stipulated here https://reactjs.org/docs/hooks-rules.html it will not work.
How can I then have a routing solution for NextJS to be callable in regular Javascript ?
So If you're using purely React.js (without Next.js on top of it), you can simple do it this way:
Import React from 'react'
export const handleRoutes = (url) => {
const history = React.useHistory()
return history.push(url)
}
Then You'd import this regular js function in any of your react files, like this:
import { handleRoutes } from 'fileName.js'
<button onClick={() => handleRoutes("/routeToBeRedirectedTo")}> Click to redirect </button>
However when using Nextjs I'm not sure that the above way would work. My personal method would be simply implementing this function (in a utility.js file):
export const handleRedirect = (router, url) => {
return router.push(url)}
Then just importing the function & useRouter hook in the file you want:
import { handleRedirect } from "./utility.js"
import { useRouter } from "next/router"
const router = useRouter
Then inside your JSX return statement:
<button onClick={() => handleRedirect(router, "/routeToBeRedirectedTo")}> Click to redirect </button>
And if it's a redirect after sign in/sign up, just simply useEffect like so:
// depends if you're storing your user credentials in your local storage or cookies, this example below would be if your User credentials are stored in localstorage
const user = JSON.parse(localstorage.getItem("user"))
UseEffect(() => {
if (user) return handleRedirect(router, "/routeToBeRedirectedTo")
}, [user])
Trying to create an xterm react component in Next.js I got stuck as I'm not able to get over an error message I've never got before.
I'm trying to import a npm client-side module called xterm, but if I add the import line the application crashes.
import { Terminal } from 'xterm'
The error reads Server Error... ReferenceError: self is not defined
and then shows this chunk of code as Source
module.exports = require("xterm");
According to some research I did, this has to do with Webpack and could be helped if something like this was done:
output: {
globalObject: 'this'
}
Would you know how to fix this?
The error occurs because the library requires Web APIs to work, which are not available when Next.js pre-renders the page on the server-side.
In your case, xterm tries to access the window object which is not present on the server. To fix it, you have to dynamically import xterm so it only gets loaded on the client-side.
There are a couple of ways to achieve this in Next.js.
#1 Using dynamic import()
Move the import to your component's useEffect, then dynamically import the library and add your logic there.
useEffect(() => {
const initTerminal = async () => {
const { Terminal } = await import('xterm')
const term = new Terminal()
// Add logic with `term`
}
initTerminal()
}, [])
#2 Using next/dynamic with ssr: false
Create a component where you add the xterm logic.
// components/terminal-component
import { Terminal } from 'xterm'
function TerminalComponent() {
const term = new Terminal()
// Add logic around `term`
return <></>
}
export default TerminalComponent
Then dynamically import that component when using it.
import dynamic from 'next/dynamic'
const TerminalComponent = dynamic(() => import('<path-to>/components/terminal-component'), {
ssr: false
})
As an alternative, you could add the logic directly when dynamically importing the library with next/dynamic to avoid having an extra file for it.
import dynamic from 'next/dynamic'
const Terminal = dynamic(
{
loader: () => import('xterm').then((mod) => mod.Terminal),
render: (props, Terminal) => {
const term = new Terminal()
// Add logic with `term`
return <></>
}
},
{
ssr: false
}
)
I'm trying to make a thin wrapper to the "jsoneditor" library using a functionnal component. I'm rather new to React and worked so far mainly with hooks. So I tried to adapt the example given by the author of the library to use hooks:
https://github.com/josdejong/jsoneditor/tree/master/examples/react_demo
This is what I came up with so far:
import React, {useRef, useState, useEffect, useCallback} from 'react'
import JSONEditor from 'jsoneditor'
import styles from './JSONEditorReact.module.css'
import 'jsoneditor/dist/jsoneditor.css';
function App(){
const [json, setJson] = useState({some_key:"some_value"})
function onChangeJson(json){
setJson(json)
}
return <JSONEditorReact onChangeJson={onChangeJson} json={json}/>
}
function JSONEditorReact({onChangeJson, json}){
const containerRef = useRef()
const editorRef = useRef() // used as a namespace to have a reference to the jsoneditor object
useEffect(
() => {
console.log("mounting")
const options = {
modes: ['tree','form','view','text'],
onChangeJSON: onChangeJson
}
editorRef.current = new JSONEditor(containerRef.current, options)
return () => editorRef.current.destroy()
},
[] //eslint complains about the missing dependency "onChangeJson" here
)
useEffect(
() => {
console.log("updating")
editorRef.current.update(json)
},
[json]
)
return (
<div className={styles.container} ref={containerRef} />
)
}
export default App;
It works - but eslint complains about onChangeJson being a missing dependency in useEffect. If I add it as a dependency, useEffect runs each time the user inputs something into the json editor. This implies that the user looses focus on the editor each time he enters a character. My understanding is that when it occurs, setJson function of App is called, so App component is refreshed, causing the onChangeJson function to be-reinstanciated, so the first useEffect is rerun, and a new JSONEditor is instanciated.
I had some ideas but they don't seem satisfying:
define onChangeJson with useCallback - issue : I find it daunting to call useCallback each time I want to use my component
pass the setter function setJson of App as the "onChangeJson" property of JSONEditorReact - issue: what if I want to perform more actions than just setting the state in my callback?
Any more relevant ideas to solve the missing dependency issue without running the first useEffect on each input?
Is this a kind of use case where class components are more relevant than functional components using hooks? (the wrapper using class components looks more straightforward than mine, where I had to use a ref to create a namespace to hold my JSONEditor instance)