Use existing cd alias in the script that fnm env --shell powershell --use-on-cd emits

[ravindUwU]

Problem

On PowerShell, fnm env currently emits the following 👇, which alises cd to Set-LocationWithFnm:

# environment variables set with $env:... = ...
function global:Set-FnmOnLoad { fnm use --silent-if-unchanged }
function global:Set-LocationWithFnm { param($path); if ($path -eq $null) {Set-Location} else {Set-Location $path}; Set-FnmOnLoad }
Set-Alias -Scope global cd_with_fnm Set-LocationWithFnm
Set-Alias -Option AllScope -Scope global cd Set-LocationWithFnm
Set-FnmOnLoad

Consequently, if cd is already aliased to a different command (e.g., as part of one's dotfiles, or a different command that similarly "patches" cd), fnm env | iex "drops" the current alias and resets it back to Set-Location.

For example,

1. cd is aliased to print out the path being navigated to, as a contrived example:

   function global:customCd {
   	param ($path)
   	Write-Host "customCd: $path"
   	Set-Location $path
   }
   Set-Alias 'cd' 'customCd' -Option AllScope -Scope Global

   ...which has the following effect:

   PS ~> cd Projects
   customCd: Projects
   PS ~/Projects>
   

2. FNM is loaded with fnm env --shell powershell --use-on-cd | Out-String | Invoke-Expression.

3. cd now prints:

   PS ~> cd Projects/jsProject
   Using Node v22.12.0
   PS ~/Projects/jsProject>
   

   ...and global:customCd from step 1 is no longer invoked.

Proposed Solution

Thoughts on emitting a script like 👇? I've only included the cd-related bits; Set-FnmOnLoad and Set-LocationWithFnm are unchanged and omitted for brevity.

$global:cdBeforeFnm = (Get-Alias 'cd' -Scope Global -ErrorAction Ignore).ReferencedCommand
if ($null -eq $global:cdBeforeFnm) { $global:cdBeforeFnm = Get-Command Set-Location }

function global:cdWithFnm {
	param ($path)
	if ($null -eq $path) { & $global:cdBeforeFnm } else { & $global:cdBeforeFnm $path }
	global:Set-FnmOnLoad
}

Set-Alias 'cd' 'global:cdWithFnm' -Option AllScope -Scope Global

...which uses the command that cd references at the time FNM is loaded, instead of always using Set-Location, thereby also invoking global:customCd:

PS ~> cd Projects/jsProject
customCd: Projects/jsProject
Using Node v22.12.0
PS ~/Projects/jsProject>