In my component's render function I have:
render() {
const items = ['EN', 'IT', 'FR', 'GR', 'RU'].map((item) => {
return (<li onClick={this.onItemClick.bind(this, item)} key={item}>{item}</li>);
});
return (
<div>
...
<ul>
{items}
</ul>
...
</div>
);
}
everything renders fine, however when clicking the <li> element I receive the following error:
Uncaught Error: Invariant Violation: Objects are not valid as a React
child (found: object with keys {dispatchConfig, dispatchMarker,
nativeEvent, target, currentTarget, type, eventPhase, bubbles,
cancelable, timeStamp, defaultPrevented, isTrusted, view, detail,
screenX, screenY, clientX, clientY, ctrlKey, shiftKey, altKey,
metaKey, getModifierState, button, buttons, relatedTarget, pageX,
pageY, isDefaultPrevented, isPropagationStopped, _dispatchListeners,
_dispatchIDs}). If you meant to render a collection of children, use an array instead or wrap the object using createFragment(object) from
the React add-ons. Check the render method of Welcome.
If I change to this.onItemClick.bind(this, item) to (e) => onItemClick(e, item) inside the map function everything works as expected.
If someone could explain what I am doing wrong and explain why do I get this error, would be great
UPDATE 1:
onItemClick function is as follows and removing this.setState results in error disappearing.
onItemClick(e, item) {
this.setState({
lang: item,
});
}
But I cannot remove this line as I need to update state of this component
I was having this error and it turned out to be that I was unintentionally including an Object in my JSX code that I had expected to be a string value:
return (
<BreadcrumbItem href={routeString}>
{breadcrumbElement}
</BreadcrumbItem>
)
breadcrumbElement used to be a string but due to a refactor had become an Object. Unfortunately, React's error message didn't do a good job in pointing me to the line where the problem existed. I had to follow my stack trace all the way back up until I recognized the "props" being passed into a component and then I found the offending code.
You'll need to either reference a property of the object that is a string value or convert the Object to a string representation that is desirable. One option might be JSON.stringify if you actually want to see the contents of the Object.
So I got this error when trying to display the createdAt property which is a Date object. If you concatenate .toString() on the end like this, it will do the conversion and eliminate the error. Just posting this as a possible answer in case anyone else ran into the same problem:
{this.props.task.createdAt.toString()}
I just got the same error but due to a different mistake: I used double braces like:
{{count}}
to insert the value of count instead of the correct:
{count}
which the compiler presumably turned into {{count: count}}, i.e. trying to insert an Object as a React child.
Just thought I would add to this as I had the same problem today, turns out that it was because I was returning just the function, when I wrapped it in a <div> tag it started working, as below
renderGallery() {
const gallerySection = galleries.map((gallery, i) => {
return (
<div>
...
</div>
);
});
return (
{gallerySection}
);
}
The above caused the error. I fixed the problem by changing the return() section to:
return (
<div>
{gallerySection}
</div>
);
...or simply:
return gallerySection
React child(singular) should be type of primitive data type not object or it could be JSX tag(which is not in our case). Use Proptypes package in development to make sure validation happens.
Just a quick code snippet(JSX) comparision to represent you with idea :
Error : With object being passed into child
<div>
{/* item is object with user's name and its other details on it */}
{items.map((item, index) => {
return <div key={index}>
--item object invalid as react child--->>>{item}</div>;
})}
</div>
Without error : With object's property(which should be primitive, i.e. a string value or integer value) being passed into child.
<div>
{/* item is object with user's name and its other details on it */}
{items.map((item, index) => {
return <div key={index}>
--note the name property is primitive--->{item.name}</div>;
})}
</div>
TLDR; (From the source below) : Make sure all of the items you're rendering in JSX are primitives and not objects when using React. This error usually happens because a function involved in dispatching an event has been given an unexpected object type (i.e passing an object when you should be passing a string) or part of the JSX in your component is not referencing a primitive (i.e. this.props vs this.props.name).
Source - codingbismuth.com
Mine had to do with forgetting the curly braces around props being sent to a presentational component:
Before:
const TypeAheadInput = (name, options, onChange, value, error) => {
After
const TypeAheadInput = ({name, options, onChange, value, error}) => {
I too was getting this "Objects are not valid as a React child" error and for me the cause was due to calling an asynchronous function in my JSX. See below.
class App extends React.Component {
showHello = async () => {
const response = await someAPI.get("/api/endpoint");
// Even with response ignored in JSX below, this JSX is not immediately returned,
// causing "Objects are not valid as a React child" error.
return (<div>Hello!</div>);
}
render() {
return (
<div>
{this.showHello()}
</div>
);
}
}
What I learned is that asynchronous rendering is not supported in React. The React team is working on a solution as documented here.
Mine had to do with unnecessarily putting curly braces around a variable holding a HTML element inside the return statement of the render() function. This made React treat it as an object rather than an element.
render() {
let element = (
<div className="some-class">
<span>Some text</span>
</div>
);
return (
{element}
)
}
Once I removed the curly braces from the element, the error was gone, and the element was rendered correctly.
For anybody using Firebase with Android, this only breaks Android. My iOS emulation ignores it.
And as posted by Apoorv Bankey above.
Anything above Firebase V5.0.3, for Android, atm is a bust. Fix:
npm i --save firebase#5.0.3
Confirmed numerous times here
https://github.com/firebase/firebase-js-sdk/issues/871
I also have the same problem but my mistake is so stupid. I was trying to access object directly.
class App extends Component {
state = {
name:'xyz',
age:10
}
render() {
return (
<div className="App">
// this is what I am using which gives the error
<p>I am inside the {state}.</p>
//Correct Way is
<p>I am inside the {this.state.name}.</p>
</div>
);
}
}
Typically this pops up because you don't destructure properly. Take this code for example:
const Button = text => <button>{text}</button>
const SomeForm = () => (
<Button text="Save" />
)
We're declaring it with the = text => param. But really, React is expecting this to be an all-encompassing props object.
So we should really be doing something like this:
const Button = props => <button>{props.text}</button>
const SomeForm = () => (
<Button text="Save" />
)
Notice the difference? The props param here could be named anything (props is just the convention that matches the nomenclature), React is just expecting an object with keys and vals.
With object destructuring you can do, and will frequently see, something like this:
const Button = ({ text }) => <button>{text}</button>
const SomeForm = () => (
<Button text="Save" />
)
...which works.
Chances are, anyone stumbling upon this just accidentally declared their component's props param without destructuring.
Just remove the curly braces in the return statement.
Before:
render() {
var rows = this.props.products.map(product => <tr key={product.id}><td>{product.name}</td><td>{product.price}</td></tr>);
return {rows}; // unnecessary
}
After:
render() {
var rows = this.props.products.map(product => <tr key={product.id}><td>{product.name}</td><td>{product.price}</td></tr>);
return rows; // add this
}
I had the same problem because I didn't put the props in the curly braces.
export default function Hero(children, hero ) {
return (
<header className={hero}>
{children}
</header>
);
}
So if your code is similar to the above one then you will get this error.
To resolve this just put curly braces around the props.
export default function Hero({ children, hero }) {
return (
<header className={hero}>
{children}
</header>
);
}
I got the same error, I changed this
export default withAlert(Alerts)
to this
export default withAlert()(Alerts).
In older versions the former code was ok , but in later versions it throws an error. So use the later code to avoid the errror.
This was my code:
class App extends Component {
constructor(props){
super(props)
this.state = {
value: null,
getDatacall : null
}
this.getData = this.getData.bind(this)
}
getData() {
// if (this.state.getDatacall === false) {
sleep(4000)
returnData("what is the time").then(value => this.setState({value, getDatacall:true}))
// }
}
componentDidMount() {
sleep(4000)
this.getData()
}
render() {
this.getData()
sleep(4000)
console.log(this.state.value)
return (
<p> { this.state.value } </p>
)
}
}
and I was running into this error. I had to change it to
render() {
this.getData()
sleep(4000)
console.log(this.state.value)
return (
<p> { JSON.stringify(this.state.value) } </p>
)
}
Hope this helps someone!
If for some reason you imported firebase. Then try running npm i --save firebase#5.0.3. This is because firebase break react-native, so running this will fix it.
In my case it was i forgot to return a html element frm the render function and i was returning an object . What i did was i just wrapped the {items} with a html element - a simple div like below
<ul>{items}</ul>
Just remove the async keyword in the component.
const Register = () => {
No issues after this.
In my case, I added a async to my child function component and encountered this error. Don't use async with child component.
I got this error any time I was calling async on a renderItem function in my FlatList.
I had to create a new function to set my Firestore collection to my state before calling said state data inside my FlatList.
My case is quite common when using reduce but it was not shared here so I posted it.
Normally, if your array looks like this:
[{ value: 1}, {value: 2}]
And you want to render the sum of value in this array. JSX code looks like this
<div>{array.reduce((acc, curr) => acc.value + curr.value)}</div>
The problem happens when your array has only one item, eg: [{value: 1}].
(Typically, this happens when your array is the response from server so you can not guarantee numbers of items in that array)
The reduce function returns the element itself when array has only one element, in this case it is {value: 1} (an object), it causes the Invariant Violation: Objects are not valid as a React child error.
You were just using the keys of object, instead of the whole object!
More details can be found here: https://github.com/gildata/RAIO/issues/48
import React, { Component } from 'react';
import PropTypes from 'prop-types';
class SCT extends Component {
constructor(props, context) {
super(props, context);
this.state = {
data: this.props.data,
new_data: {}
};
}
componentDidMount() {
let new_data = this.state.data;
console.log(`new_data`, new_data);
this.setState(
{
new_data: Object.assign({}, new_data)
}
)
}
render() {
return (
<div>
this.state.data = {JSON.stringify(this.state.data)}
<hr/>
<div style={{color: 'red'}}>
{this.state.new_data.name}<br />
{this.state.new_data.description}<br />
{this.state.new_data.dependtables}<br />
</div>
</div>
);
}
}
SCT.propTypes = {
test: PropTypes.string,
data: PropTypes.object.isRequired
};
export {SCT};
export default SCT;
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
If you are using Firebase and seeing this error, it's worth to check if you're importing it right. As of version 5.0.4 you have to import it like this:
import firebase from '#firebase/app'
import '#firebase/auth';
import '#firebase/database';
import '#firebase/storage';
Yes, I know. I lost 45 minutes on this, too.
I just put myself through a really silly version of this error, which I may as well share here for posterity.
I had some JSX like this:
...
{
...
<Foo />
...
}
...
I needed to comment this out to debug something. I used the keyboard shortcut in my IDE, which resulted in this:
...
{
...
{ /* <Foo /> */ }
...
}
...
Which is, of course, invalid -- objects are not valid as react children!
I'd like to add another solution to this list.
Specs:
"react": "^16.2.0",
"react-dom": "^16.2.0",
"react-redux": "^5.0.6",
"react-scripts": "^1.0.17",
"redux": "^3.7.2"
I encountered the same error:
Uncaught Error: Objects are not valid as a React child (found: object
with keys {XXXXX}). If you meant to render a collection of children,
use an array instead.
This was my code:
let payload = {
guess: this.userInput.value
};
this.props.dispatch(checkAnswer(payload));
Solution:
// let payload = {
// guess: this.userInput.value
// };
this.props.dispatch(checkAnswer(this.userInput.value));
The problem was occurring because the payload was sending the item as an object. When I removed the payload variable and put the userInput value into the dispatch everything started working as expected.
If in case your using Firebase any of the files within your project.
Then just place that import firebase statement at the end!!
I know this sounds crazy but try it!!
I have the same issue, in my case,
I update the redux state, and new data parameters did not match old parameters, So when I want to access some parameters it through this Error,
Maybe this experience help someone
My issue was simple when i faced the following error:
objects are not valid as a react child (found object with keys {...}
was just that I was passing an object with keys specified in the error while trying to render the object directly in a component using {object} expecting it to be a string
object: {
key1: "key1",
key2: "key2"
}
while rendering on a React Component, I used something like below
render() {
return this.props.object;
}
but it should have been
render() {
return this.props.object.key1;
}
If using stateless components, follow this kind of format:
const Header = ({pageTitle}) => (
<h1>{pageTitle}</h1>
);
export {Header};
This seemed to work for me
Something like this has just happened to me...
I wrote:
{response.isDisplayOptions &&
{element}
}
Placing it inside a div fixed it:
{response.isDisplayOptions &&
<div>
{element}
</div>
}
I'm new to React and I'm stuck trying to get this onClick function to work properly.
I have a component "Row" that contains a dynamic list of divs that it gets from a function and returns them:
export function Row({parentState, setParentState}) {
let divList = getDivList(parentState, setParentState);
return (
<div>
{divList}
</div>
)
}
Say parentState could just be:
[["Name", "info"],
["Name2", "info2"]]
The function returns a list of divs, each with their own className determined based on data in the parentState. Each one needs to be able to update its own info in parentState with an onClick function, which must in turn update the className so that the appearance of the div can change. My code so far seems to update the parentState properly (React Devtools shows the changes, at least when I navigate away from the component and then navigate back, for some reason), but won't update the className until a later event. Right now it looks like this:
export function getDivList(parentState, setParentState) {
//parentState is an array of two-element arrays
const divList = parentState.map((ele, i) => {
let divClass = "class" + ele[1];
return (
<div
key={ele, i}
className={divClass}
onClick={() => {
let newParentState =
JSON.parse(JSON.stringify(parentState);
newParentState[i][1] = "newInfo";
setParentState(newParentState);}}>
{ele[0]}
</div>
)
}
return divList;
}
I have tried to use useEffect, probably wrong, but no luck. How should I do this?
Since your Row component has parentState as a prop, I assume it is a direct child of this parent component that contains parentState. You are trying to access getDivList in Row component without passing it as a prop, it won't work if you write your code this way.
You could use the children prop provided by React that allow you to write a component with an opening and closing tag: <Component>...</Component>. Everything inside will be in the children. For your code it would looks like this :
import React from 'react';
import { render } from 'react-dom';
import './style.css';
const App = () => {
const [parentState, setParentState] = React.useState([
['I am a div', 'bg-red'],
['I am another div', 'bg-red'],
]);
React.useEffect(
() => console.log('render on ParentState changes'),
[parentState]
);
const getDivList = () => {
return parentState.map((ele, i) => {
return (
<div
key={(ele, i)}
className={ele[1]}
onClick={() => {
// Copy of your state with the spread operator (...)
let newParentState = [...parentState];
// We don't know the new value here, I just invented it for the example
newParentState[i][1] = [newParentState[i][1], 'bg-blue'];
setParentState(newParentState);
}}
>
{ele[0]}
</div>
);
});
};
return <Row>{getDivList()}</Row>;
};
const Row = ({ children }) => {
return <>{children}</>;
};
render(<App />, document.getElementById('root'));
And a bit of css for the example :
.bg-red {
background-color: darkred;
color: white;
}
.bg-blue {
background-color:aliceblue;
}
Here is a repro on StackBlitz so you can play with it.
I assumed the shape of the parentState, yu will have to adapt by your needs but it should be something like that.
Now, if your data needs to be shared across multiple components, I highly recommand using a context. Here is my answer to another post where you'll find a simple example on how to implement a context Api.
I am using Jest and Enzyme to test my React-Mobx app. I have come to a problem where I am accessing different values under the same prop name. As you can see I am accessing different properties under the same FilterssAction prop name.
#inject('RootStore', 'FiltersAction')
#observer
class ExpenseListFilters extends Component {
state = {
calendarFocused: null
}
onDatesChange = ({startDate, endDate}) => {
this.props.FiltersAction.setStartDate(startDate)
this.props.FiltersAction.setEndDate(endDate)
}
onTextChange = (e) => {
this.props.FiltersAction.setTextFilter(e.target.value)
}
...
When I write my test it fails. I need to pass props to shallow rendered component. So I am passing different values under same. This is not working, I keep getting an error TypeError: _this.props.FiltersAction.setTextFilter is not a function
How do I test this?
let setStartDateSpy, setEndDateSpy, setTextFilterSpy, sortByDateSpy, sortByAmountSpy, FiltersStore, wrapper
beforeEach(() => {
setStartDateSpy = {setStartDate: jest.fn()}
setEndDateSpy = {setEndDate: jest.fn()}
setTextFilterSpy = {setTextFilter: jest.fn()}
FiltersStore = {FiltersStore: {filters: filters}}
wrapper = shallow(
<ExpenseListFilters.wrappedComponent
FiltersAction = {
setStartDateSpy,
setEndDateSpy,
setTextFilterSpy
}
RootStore = {FiltersStore}
/>
)
})
test('should handle text change', () => {
const value = 'rent'
wrapper.find('input').at(0).simulate('change', {
target: {value}
})
expect(setTextFilterSpy).toHaveBeenLastCalledWith(value)
})
It looks like your component is expecting FiltersAction to be an object whose values are functions.
In your application code, you can see that it as accessing the FiltersActions prop with dot-notation, and executing it as a function. For example, this.props.FiltersAction.setEndDate(endDate)
To pass a prop as an object, you need to wrap it again with curly braces. So, in your test, try passing FiltersAction as an object like below:
wrapper = shallow(
<ExpenseListFilters.wrappedComponent
FiltersAction = {{
setStartDate: setStartDateSpy,
setDentDate: setEndDateSpy,
setTextFilter: setTextFilterSpy
}}
RootStore = {FiltersStore}
/>
)
Note that in your example, you were:
Not double-wrapping your object w/ curly braces
Creating the object literal with computed property keys. That is, when you don't explicitly provide a property name, the resulting object will create the property name based on the variable name. Here is a good resource for learning more about enhanced object literals in ES6 So your generated object did not include the properties your application code was expecting and was attempting to call undefined as a function