React Hooks Mobx: invalid hook call. Hooks can only be called inside of the body of a function component

Question

I am using React Hooks and when I wrap my component with observer from mobx, I am getting this error. What can be the problem? Is it possible to use mobx with React Hooks?

import classnames from 'classnames';
import { observer } from 'mobx-react';
import React, { useState } from 'react';
import { Link } from 'react-router-dom';
import ViewStore from '../../../store/ViewStore';

interface INavbarProps {
  viewStore: ViewStore;
}

const Navbar = observer((props: INavbarProps) => {
  const { authed } = props.viewStore;

  const [drawerIsOpen, setState] = useState(false);

  function toggleMenu() {
    drawerIsOpen ? setState(false) : setState(true);
  }

  return (
    <div>
      <Link to="/">Home</Link>
      <Link to="/admin">Admin</Link>
      <Link to="/all">All</Link>
      {authed ? <Link to="/">Logout</Link> : <Link to="/login">Login</Link>}

      <div onClick={toggleMenu}>
        Open Menu
      </div>

      <div className={classnames('drawer', {
        drawer_open: drawerIsOpen,
      })} />

      <div onClick={toggleMenu} className={drawerIsOpen ? 'backdrop' : ''}></div>
    </div>
  );
});

export default Navbar;

Colin Ricardo · Answer 1 · 2019-04-17T11:31:14.343

5

The MobX observer will result in a class component under the hood.

As per here, you can work around this by doing:

(props) => <Observer>{() => rendering}</Observer>

instead of:

observer((props) => rendering)

Example

import React from "react";
import { Observer } from "mobx-react";

const MobxFunctionalComponentObserver = props => (
  <Observer
    inject={stores => ({ ... })}
    render={props => (
      ... 
    )}
  />
);

edited Apr 17 '19 at 11:31

answered Apr 17 '19 at 11:14

Colin Ricardo

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Thanks! What's the Observer component and how can it be applied to my piece of code? – lecham Apr 17 '19 at 11:17
Updated the answer. Alternatively, see @Tholle's answer for a better longterm solution. – Colin Ricardo Apr 17 '19 at 11:31

score 5 · Accepted Answer · answered Apr 17 '19 at 11:16

It's currently not supported to use hooks with the mobx-react package since it creates a class component under the hood.

You can use the 6.0.0 release candidate that will be released soon, which does support hooks.

package.json

{
  "dependencies": {
    "mobx-react": "6.0.0-rc.4"
  }
}

React Hooks Mobx: invalid hook call. Hooks can only be called inside of the body of a function component

2 Answers2

Example

Linked