javascript - react useEffect comparing objects

Question

I am using react useEffect hooks and checking if an object has changed and only then run the hook again.

My code looks like this.

const useExample = (apiOptions) => {
    const [data, updateData] = useState([]);
    useEffect(() => {
       const [data, updateData] = useState<any>([]);
        doSomethingCool(apiOptions).then(res => {               
           updateData(response.data);
       })
    }, [apiOptions]);

    return {
        data
    };
};

Unfortunately it keeps running as the objects are not being recognised as being the same.

I believe the following is an example of why.

const objA = {
   method: 'GET'
}

const objB = {
   method: 'GET'
}

console.log(objA === objB)

Answer 1

Use apiOptions as state value

I'm not sure how you are consuming the custom hook but making apiOptions a state value by using useState should work just fine. This way you can serve it to your custom hook as a state value like so:

const [apiOptions, setApiOptions] = useState({ a: 1 })
const { data } = useExample(apiOptions)

This way it's going to change only when you use setApiOptions.

Example #1

import { useState, useEffect } from 'react';

const useExample = (apiOptions) => {
  const [data, updateData] = useState([]);
  
  useEffect(() => {
    console.log('effect triggered')
  }, [apiOptions]);

  return {
    data
  };
}
export default function App() {
  const [apiOptions, setApiOptions] = useState({ a: 1 })
  const { data } = useExample(apiOptions);
  const [somethingElse, setSomethingElse] = useState('default state')

  return <div>
    <button onClick={() => { setApiOptions({ a: 1 }) }}>change apiOptions</button>
    <button onClick={() => { setSomethingElse('state') }}>
      change something else to force rerender
    </button>
  </div>;
}