nvm.sh is slow (200ms+)

[dy-dx]

On my system (OSX 10.9.5 & bash 4.3.27), nvm adds a lot of time to my .bash_profile:

$ time source ~/.nvm/nvm.sh

real    0m0.218s
user    0m0.107s
sys 0m0.163s

--This is much slower than rvm--:

$ time source ~/.rvm/scripts/rvm

real    0m0.011s
user    0m0.005s
sys 0m0.006s

I do not use .nvmrc files.

[ljharb]

#337 would alleviate this by requiring much less code to be sourced.

If someone were to profile the script and figure out which parts were slowest, I'd be happy to try to speed them up. PRs are also welcome :-)

[dy-dx]

@ljharb My apologies -- I just realized that RVM takes just about as long as NVM when sourcing it for the first time. It exports a rvm_loaded_flag so it get skipped upon subsequent loading

[maxpoletaev]

In zsh I use lazy loading for source files.
This is not a solution but shell runs faster.

lazy_source () {
    eval "$1 () { [ -f $2 ] && source $2 && $1 \$@ }"
}

NVM_SOURCE=$HOME/.nvm/nvm.sh
lazy_source nvm $NVM_SOURCE

[ljharb]

not a bad idea. It could even be more specific as in:

nvm() { . "$NVM_DIR/nvm.sh" ; nvm $@ ; }

However, that wouldn't detect nvmrc or a default nvm alias and use them :-/

[daneroo]

Same here... still looking for a solution..

 $ time source ~/.nvm/nvm.sh 
 0.799s

[bgerm]

This is pretty slow:

NVM_NPM_PREFIX="$(npm config get prefix)"

$ time npm config get prefix
npm config get prefix  0.23s user 0.03s system 103% cpu 0.245 total

This line is about 0.03s and gets called twice:

VERSION="$(nvm_ls "$PATTERN" | command tail -n1)"

This line is also about 0.03s:

VERSION="$(nvm_match_version "$PROVIDED_VERSION")"

[ljharb]

Any time npm is called, it's slow, sadly.

However, I think the risks of people unknowingly having a prefix set are more important than a small delay opening the shell. I'll continue working on speeding things up.

[bgerm]

Thanks, @ljharb. The delay was more of an observation than an annoyance.

[dreyks]

$ time source ~/.nvm/nvm.sh

real    0m3.163s
user    0m1.504s
sys     0m1.172s

clean install of nvm, no .nvmrc.

what could be the reason?

[ljharb]

@dreyks Likely because npm config get prefix is slow. There's no way around that yet.

[dreyks]

@ljharb this still leaves about 2.5 seconds for the rest

$ time npm config get prefix
/home/user/.nvm/versions/node/v6.3.1

real    0m0.753s
user    0m0.564s
sys     0m0.236s

this isn't super critical, cause it happens only when I open another shell, but still I wonder if my setup is wrong

[ljharb]

@dreyks if you try nvm unalias default, does it still happen?