N: Switch current node version quickly

[tekumara]

Problem

I'd like to switch the current node version to an already downloaded version of node quickly (ie: ~100ms). It currently takes 3.5 - 7 secs.

$ time n 12
   installed : v12.18.3 (with npm 6.14.6)
n 12  0.26s user 1.36s system 45% cpu 3.597 total

Configuration Details

$ n --version
6.7.0

$ command -v node
/Users/tekumara/.n/bin/node

$ node -p process.platform
darwin

[shadowspawn]

n does a full install, not just switching a symlink. That takes a while.

1) Do you have anti-virus on your Mac? I have seen some very slow installs (> 30 s) due to anti-virus when the file cache is cold. Try installing with anti-virus turned off to set a baseline.

2) There are far fewer files to copy if you leave npm out of the install. Try --preserve or -p.

$ time n 12
   installed : v12.18.3 (with npm 6.14.6)
n 12  0.30s user 1.99s system 44% cpu 5.141 total
$ time n 12
   installed : v12.18.3 (with npm 6.14.6)
n 12  0.28s user 1.60s system 58% cpu 3.222 total
$ time n --preserve 12
   installed : v12.18.3
n --preserve 12  0.27s user 0.46s system 39% cpu 1.835 total
$ time n --preserve 12
   installed : v12.18.3
n --preserve 12  0.24s user 0.22s system 30% cpu 1.519 total

[tekumara]

Thanks for the explanation @shadowspawn. No I don't have anti-virus installed. --preserve is definitely faster, would be nice if it were the default. I'll try some of the alternative version managers and see if they are any quicker.

[shadowspawn]

Thanks for closing with comment.

Some of the other managers switch versions by changing symlinks, or change PATH, or run a node shim to decide which node version to use. Different tradeoffs, but all faster than doing a full install so you should find a good alternative for a faster switch.