handleChange() function causing crash for some reason

[lasjorg]

1. Because of the updater function for the handleChange. You can read more about it in the post below.

setState and event.target

My React app don't work

You are not using the current state for the state update. This means the updater function is not needed and you should just be using an object. handleChange(event) { this.setState({ input: event.target.value }) } Next. The fCC React curriculum is using React v16.4.0 and because of how React 16 events work (pooling) the event target will be undefined inside the setState updater function. This is why it crashes when you type into the input Uncaught TypeError: Cannot read propert…

2. state.messages now has to be using this (without the updater function)