I decided this year to try the adventofcode2020 challenge in JS to see. I published the solutions I found in a public repository on Github. Not sure I will find solution for the upcoming challenges. 😅
Take a look at https://github.com/Slashgear/advent-of-code
Project is a lerna monorepo structure showing solution by years and days.
packages/ 2019/ day-1/ .. day-2/ .. 2020/ day-1/ .. day-2/ .. day-3/ .. day-4/ .. ..
For now, you can find solution for: