False Positive

Getting warning: “Re-rendered because the state object itself changed but it’s values are all equal.” “This usually means this component called setState when no changes in it’s state actually occurred.” “more info at http://bit.ly/wdyr02” prev state: Object {} !== Object {} :next state

I added a console log of the props, and it can be seen that its only rendering once per prop change.

The component:

class MyComp extends PureComponent {
    static whyDidYouRender = true;

    render() {
        console.log('rerendered', this.props.downloadProgress);
        return (
            <View/>
        );
    }
}

const mapStateToProps = state => ({
    downloadProgress: getDownloadProgress(state),
});

export default connect(mapStateToProps)(MyComp);

Every time the prop changes causing a rerender I get the warning above that the warning is unnecessary, which is false.

It may also be worth noting that this component is opened/hosted via react-navigation.

[vzaidman]

@parties I dont have it here where I updated react-redux and redux: https://codesandbox.io/s/whydidyourender-false-positive-demo-pjkn7

These older versions didn’t handle state changes as well as the last version. I strongly suggest using the last one.

[dihan]

Updating Redux fixed this issue for me