Millions tutorials online of CSS flexbox is about one pattern: parent dispay: flex; + one level children. However, in practice, flexbox is used in nested pattern more often than not. That is grandparent display: flex; + parent display: flex; + grandchildren. It’s very useful to know that you don’t have to use flexbox in only one level.

1. Generate an array

Github Pages + Jekyll is free and reliabe. And it’s fun to use it to make a website.

Jest mock module feature can be used for mocking whole or part of packages in your project. Check out: https://jestjs.io/docs/manual-mocks

Here is the two videos: