Invariant Violation: Objects are not valid as a React child. Check the render method of `Content`

Question

I am getting the above error once I am refreshing the page and reloading the same props by getting it from the state.I am not able to find why is it happening while reload of page , on first load page is loading fine.

  const Content = (props) => {
      if (props.tabItem.contentList !== undefined) {
        return (
          <div>
            {props.tabItem.contentList.map((tab) => {
              if (props.tabItem.currentTab === tab.tabId) {
                return (
                  <div key={props.tabItem.currentTab}>
                    {tab.content.props.children}
                  </div>
                );
              }
            })}
          </div>
        );
      }
      return (
        <div>no record</div>
      );
    };

My tabItem that saving in the state is like this:-

 tabList = [{
        tabId: '1',
        tabName: 'Test'
        isPrimary: true,
      },
      ];
      // create new contentList
      contentList = [
        {
          tabId: '1',
          content: <div> <Test1Container{...this.props} addTab={this.addTab} /></div>,
        },
      ];
      tabData = {
        tabList,
        currentTab: '1',
        contentList,
      };
this.props.addTabItem(tabData);
this.props.addTabItem is use to save the state.

Answer 1

Changes:

1. Write an else condition, if if condition fails then in that case component is not returning anything.

2. We can't use if/else inside jsx so use ternary operator for conditional rendering.

3. currentTab is present inside tabData so write it like this to access it's value:

props.tabItem.currentTab

4. Return null if condition fails inside map body.

Use this:

const Content = (props) => {
  if (props.tabItem.contentList !== undefined) {
    return (
      <div>
         {props.tabItem.contentList.map((tab) => {
            return props.tabItem.tabData.currentTab === tab.tabId ? 
                 <div key={props.tabItem.currentTab}>
                     {tab.content.props.children}
                  </div>
                  : null
         })}
      </div>
    )
  }else{
      return null
  }
}

Check this sample working snippet:

var a = <div><p>hello</p><p>world</p></div>

var App = (props) => {
    return <div>{props.a.props.children}</div>
}

ReactDOM.render(<App a={a}/>, document.getElementById('app'))

<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>

<div id='app'/>