load-nvmrc is slow

[maksimr]

load-nvmrc[1] function is very slow.
It spends around 220ms on check and it runs on every change directory(cd)

OS: macOs High Sierra
Processor: 2,2 GHz Intel Core i7
Termina: iTerm2(3.1.5)
Shell: zsh 5.3 (x86_64-apple-darwin17.0)

Test:

#!/usr/bin/env zsh
export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"

load-nvmrc() {
    local node_version="$(nvm version)"
    local nvmrc_path="$(nvm_find_nvmrc)"

    if [ -n "$nvmrc_path" ]; then
      local nvmrc_node_version=$(nvm version "$(cat "${nvmrc_path}")")
      if [ "$nvmrc_node_version" = "N/A" ]; then
        nvm install
      elif [ "$nvmrc_node_version" != "$node_version" ]; then
        nvm use
      fi
    elif [ "$node_version" != "$(nvm version default)" ]; then
      nvm use default
    fi
}

zmodload zsh/zprof
load-nvmrc
zprof

We could reduce time to 60ms if remove elif clause but 60ms is still a measurable delay.

load-nvmrc() {
    local node_version="$(nvm version)"
    local nvmrc_path="$(nvm_find_nvmrc)"

    if [ -n "$nvmrc_path" ]; then
      local nvmrc_node_version=$(nvm version "$(cat "${nvmrc_path}")")
      if [ "$nvmrc_node_version" = "N/A" ]; then
        nvm install
      elif [ "$nvmrc_node_version" != "$node_version" ]; then
        nvm use
      fi
    fi
}

nvm version takes 53ms

num  calls                time                       self            name
-----------------------------------------------------------------------------------
 1)    2          31.10    15.55   53.93%     31.10    15.55   53.93%  nvm_tree_contains_path
 2)    1          49.65    49.65   86.09%     15.99    15.99   27.72%  nvm_ls_current
 3)    2          57.65    28.82   99.96%      7.91     3.96   13.72%  nvm
 4)    1           2.56     2.56    4.44%      2.56     2.56    4.44%  nvm_echo
 5)    1          49.74    49.74   86.24%      0.09     0.09    0.15%  nvm_version
 6)    1          57.67    57.67  100.00%      0.02     0.02    0.04%  load-nvmrc

-----------------------------------------------------------------------------------

 6)    1          57.67    57.67  100.00%      0.02     0.02    0.04%  load-nvmrc
       1/2        57.65    57.65   99.96%      4.05     4.05             nvm [3]

-----------------------------------------------------------------------------------

       1/2        57.65    57.65   99.96%      4.05     4.05             load-nvmrc [6]
       1/2        53.60    53.60   92.95%      3.86     3.86             nvm [3]
 3)    2          57.65    28.82   99.96%      7.91     3.96   13.72%  nvm
       1/1        49.74    49.74   86.24%      0.09     0.09             nvm_version [5]
       1/2        53.60    53.60   92.95%      3.86     3.86             nvm [3]

-----------------------------------------------------------------------------------

       1/1        49.74    49.74   86.24%      0.09     0.09             nvm [3]
 5)    1          49.74    49.74   86.24%      0.09     0.09    0.15%  nvm_version
       1/1        49.65    49.65   86.09%     15.99    15.99             nvm_ls_current [2]

-----------------------------------------------------------------------------------

       1/1        49.65    49.65   86.09%     15.99    15.99             nvm_version [5]
 2)    1          49.65    49.65   86.09%     15.99    15.99   27.72%  nvm_ls_current
       1/1         2.56     2.56    4.44%      2.56     2.56             nvm_echo [4]
       2/2        31.10    15.55   53.93%     31.10    15.55             nvm_tree_contains_path [1]

-----------------------------------------------------------------------------------

       2/2        31.10    15.55   53.93%     31.10    15.55             nvm_ls_current [2]
 1)    2          31.10    15.55   53.93%     31.10    15.55   53.93%  nvm_tree_contains_path

-----------------------------------------------------------------------------------

       1/1         2.56     2.56    4.44%      2.56     2.56             nvm_ls_current [2]
 4)    1           2.56     2.56    4.44%      2.56     2.56    4.44%  nvm_echo

[1] - https://github.com/creationix/nvm#calling-nvm-use-automatically-in-a-directory-with-a-nvmrc-file

[ljharb]

This is just a suggestion in the readme; its code isn't actually part of nvm. If you'd like to PR in improvements to it, that'd be appreciated!

[maksimr]

@ljharb that is true, but this function use nvm's functions

for example take nvm_tree_contains_path

2          31.10    15.55   53.93%     31.10    15.55                  nvm_ls_current [2]
2          31.10    15.55   53.93%     31.10    15.55   53.93%  nvm_tree_contains_path

it takes 31ms

and if change this code

  local pathdir
  pathdir=$(dirname "${node_path}")
  while [ "${pathdir}" != "" ] && [ "${pathdir}" != "." ] && [ "${pathdir}" != "/" ] && [ "${pathdir}" != "${tree}" ]; do
    pathdir=$(dirname "${pathdir}")
  done
  [ "${pathdir}" = "${tree}" ]

on something like this

  [ "$tree${node_path#$tree}" = "${node_path}" ]

you could reduce the time from 31.10 to 0.11ms

Thanks

[ljharb]

@maksimr now that seems much more compelling a change to me. Would you be willing to make a PR for that? :-D

[baaart]

I have similar problem nvm takes to much time to start, stats below. Any sollution for that?

-----------------------------------------------------------------------------------
1)    1         651.20   651.20   32.86%    651.05   651.05   32.85%  nvm_die_on_prefix
2)    2        1504.45   752.22   75.91%    553.93   276.96   27.95%  nvm
3)    1        1800.55  1800.55   90.85%    296.10   296.10   14.94%  nvm_auto
4)    1         299.13   299.13   15.09%    268.28   268.28   13.54%  nvm_ensure_version_installed
5)    2         140.77    70.39    7.10%    110.81    55.40    5.59%  compinit
6)    1          30.85    30.85    1.56%     30.85    30.85    1.56%  nvm_is_version_installed
7)    4          29.96     7.49    1.51%     29.96     7.49    1.51%  compaudit
8)    1          12.31    12.31    0.62%     12.31    12.31    0.62%  nvm_supports_source_options
9)    2           8.19     4.09    0.41%      8.19     4.09    0.41%  grep-flag-available
10)    2           7.88     3.94    0.40%      7.88     3.94    0.40%  env_default
11)   56           5.49     0.10    0.28%      5.49     0.10    0.28%  __git_alias
12)   18           1.72     0.10    0.09%      1.72     0.10    0.09%  compdef
13)    1           1.67     1.67    0.08%      1.67     1.67    0.08%  _git_wrap_commands
14)    1           0.91     0.91    0.05%      0.91     0.91    0.05%  colors
15)   18           1.14     0.06    0.06%      0.65     0.04    0.03%  _alias
16)   18           0.49     0.03    0.02%      0.49     0.03    0.02%  _safe_alias
17)    3           0.42     0.14    0.02%      0.42     0.14    0.02%  nvm_has
18)    1           0.35     0.35    0.02%      0.35     0.35    0.02%  is-at-least
19)    1           0.34     0.34    0.02%      0.34     0.34    0.02%  add-zsh-hook
20)    4           0.17     0.04    0.01%      0.17     0.04    0.01%  _bind
21)    1           0.30     0.30    0.02%      0.15     0.15    0.01%  complete
22)    3           0.09     0.03    0.00%      0.09     0.03    0.00%  is_plugin
23)    1        1812.94  1812.94   91.47%      0.07     0.07    0.00%  nvm_process_parameters
24)    1           0.02     0.02    0.00%      0.02     0.02    0.00%  bashcompinit```