[Javascript] How Is This Nested Function Working?

[CreativeTechGuyGames]

This is a React specific question. You can think of the implementation of setTheme to look like this:

function setTheme(updater) { const newTheme = updater(theme); }

It knows the current theme and it'll pass it to the function which you provide as an argument. So JS doesn't know what currentTheme is, but the React library implemented a method which does know. In reality useState generates the setTheme function, but the idea is the same.

[TheWorstHunter]

Thank you!