Uses a nodejs script to import each solution as a module and run it on the input:
node run <day> [<part>] [<repeat>]
PS D:\Stuff\aoc-2020> node run 18 1 1000
Part 1: 0.000922s
800602729153
The answer for the part is given on the latter line.
Leaving out part runs both parts for the day.
Including a repeat count over 2 (1 and 2 would parse as part if part isn't given) runs the code multiple times and averages the runtime.
PS D:\Stuff\aoc-2020> node run 18 1000
Part 1: 0.000884s
800602729153
Part 2: 0.001632s
92173009047076
The first commit for each day is the actual solutions I used for that day. Often I add later commits to neaten or speed up the code, or to try a different method - if I don't, it's because I didn't bother, not out of any specific lack :)