• Don't modify or change React component state directly. React can't keep track of those state changes and rerender accordingly
• Treat state as immutable. setState don't mutate. it compares the old state and new state and returns a new state based on the differences
• creates a pending state transition, an async operation, that will eventually and always trigger a rerender
• unidirectinal data flow - setState is part of the component's lifecycle whereas changes applied through this.state can be overwritten or out of sync
• keep track of state changes
• this.state will not trigger rerenders

# References

https://stackoverflow.com/questions/37755997/why-cant-i-directly-modify-a-components-state-really https://stackoverflow.com/questions/35867038/what-the-difference-of-this-state-and-this-setstate-in-reactjs