React JS Tutorial - #6 Component Lifecycle

Next, let's have a brief look at lifecycle hooks. We'll need one to set up the timer when it is mounted to the DOM, so that it will update every second, and another to tear it down, once the component gets unmounted. More on that in the video!

[mannypa]

Hello, thank you for your videos! Why in componentDidMount method we declare variable with this.interval, not let interval ? Is there a difference ?