React Native Change State With Unexpected Logging

For context, I am working on this React Native Tutorial The way this logs confuses me. The following is the console output when I changed an empty input field by typing 'a' then 'b

Solution 1:

setState can be an asynchronous operation, not synchronous. This means that updates to state could be batched together and not done immediately in order to get a performance boost. If you really need to do something after state has been truly updated, there's a callback parameter:

this.setState({ searchString: event.nativeEvent.text }, function(newState) {
    console.log('Changed State');
    console.log('searchString = ' + this.state.searchString);
}.bind(this));

You can read more on setState in the documentation.

https://facebook.github.io/react/docs/component-api.html