javascript – Objects are not valid as a React child. If you meant to render a collection of children, use an array instead

javascript – Objects are not valid as a React child. If you meant to render a collection of children, use an array instead

Your data homes is an array, so you would have to iterate over the array using Array.prototype.map() for it to work.

return (
    <div className=col>
      <h1>Mi Casa</h1>
      <p>This is my house y&apos;all!</p>
      {homes.map(home => <div>{home.name}</div>)}
    </div>
  );

I had a similar error while I was creating a custom modal.

const CustomModal = (visible, modalText, modalHeader) => {}

Problem was that I forgot that functional components can have only one prop passed to them, according to the REACT documentation:

This function is a valid React component because it accepts a single
“props” (which stands for properties) object argument with data and
returns a React element. We call such components “function components”
because they are literally JavaScript functions. React docs

Therefore when we want to pass several variables we need to wrap them into an object or an Array and pass the pointer to that array or object. And destructure it on the component side before invoking the component. Alternatively we can use curly braces to indicate that we are sending an object with identical property names and variables that contain the value of those properties, like in the example here. And then define the function also to destructure upon arrival of the properties contained in the object.

const CustomModal = ({visible, modalText, modalHeader}) => {}

If you have multiple values to pass to the component, you should pass an object, thus curly brackets around its properties/variables (assuming they have the same name).

javascript – Objects are not valid as a React child. If you meant to render a collection of children, use an array instead

I got the same error today but with a different scenario as compared to the scenario posted in this question. Hope the solution to below scenario helps someone.

The render function below is sufficient to understand my scenario and solution:

render() {
    let orderDetails = null;
    if(this.props.loading){
        orderDetails = <Spinner />;
    }
    if(this.props.orders.length == 0){
        orderDetails = null;
    }
    orderDetails = (
        <div>
            {
                this.props.orders && 
                this.props.orders.length > 0 && 
                this.props.orders.map(order => (
                <Order 
                    key={order.id}
                    ingredient={order.ingredients}
                    price={order.price} />
                ))
            }
        </div>
    );
    return orderDetails;
}

In above code snippet : If return orderDetails is sent as return {orderDetails} then the error posted in this question pops up despite the value of orderDetails (value as <Spinner/> or null or JSX related to <Order /> component).

Error description : react-dom.development.js:57 Uncaught Invariant Violation: Objects are not valid as a React child (found: object with keys {orderDetails}). If you meant to render a collection of children, use an array instead.

We cannot return a JavaScript object from a return call inside the render() method. The reason being React expects some JSX, false, null, undefined, true to render in the UI and NOT some JavaScript object that I am trying to render when I use return {orderDetails} and hence get the error as above.

VALID :

<div />

<div></div>

<div>{false}</div>

<div>{null}</div>

<div>{undefined}</div>

<div>{true}</div>

INVALID :

<div>{orderDetails}</div> // This is WRONG, orderDetails is an object and NOT a valid return value that React expects.

Edit: I also got this error on my companys test server used by QAs for their testing. I pointed my local code to that test server and tested the scenario in which this error was reported by QA team and found NO ERROR in my local machine. I got surprised. I re-checked multiple number of times, re-checked the scenario with QA team and I was doing right but still I was not able to replicate the issue. I consulted my fellow devs but still were not able to figure out the root cause. So keeping with the information in the error message I started scanning all the code I had deployed in my last deployment commit ( to be more specific last 4-5 commits because I suspected it could be there from last few deployments but was caught in the current deployment), especially all the components I had developed and found that there was a component – inside which there was no specified condition being met so it was returning NOTHING from it. So see below sample pseudo code. I hope it helps.

render () {
return (
    {this.props.condition1 && (
       return some jsx 1
    )}

    {this.props.condition1 && (
       return some jsx 2
    )})
}

If you see in above pseudo code if condition1 and condition2 are not met then this component will render NOTHING from it and ideally a react component must return some JSX, false, null, undefined, true from it.

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