PowerShell: Lightweight replacement function when Makefile not available

bower.json

{
  "name": "powershell-makefile",
  "description": "",
  "main": "build.ps1",
  "license": "",
  "homepage": "",
  "ignore": [
    "**/.*",
    "node_modules",
    "bower_components",
    "test",
    "tests"
  ],
  "dependencies": {
    "grunt": "^1"
  }
}

Make.ps1

# https://github.com/PowerShell/PowerShell/blob/master/docs/installation/linux.md#macos-1011
# https://msdn.microsoft.com/powershell
# https://github.com/PowerShell/PowerShell/releases/tag/v6.0.0-alpha.15

[CmdletBinding()]

Param([Parameter(Mandatory=$False,Position=1)] [string]$Command)

$Command = If ($Command) { $Command } Else { "default" }
Write-Output "Make targets ($Command)"

Function New-Target
{
    Param([string]$Source, [string]$Target)

    $Modified = If (Test-Path $Target)
    {
        ((Get-Item $Target).LastWriteTime).Ticks
    }
    Else
    {
        0
    }

    Return ((Get-Item $Source).LastWriteTime).Ticks -gt $Modified
}

If ($Command -imatch "clean")
{
    If (Test-Path ./node_modules)
    {
        Remove-Item -Recurse -Force ./node_modules
    }
    If (Test-Path ./bower_components)
    {
        Remove-Item -Recurse -Force ./bower_components
    }
    Exit 0;
}

If (New-Target ./package.json ./node_modules/package.json)
{
    $(npm install)
    Copy-Item package.json ./node_modules/package.json
}
Else
{
    Write-Output "Skipping package.json..."
}

If (New-Target ./bower.json ./bower_components/bower.json)
{
    $(node_modules/.bin/bower install)
    Copy-Item bower.json ./bower_components/bower.json
}
Else
{
    Write-Output "Skipping bower.json..."
}

package.json

{
  "name": "powershell-makefile",
  "version": "1.0.0",
  "description": "",
  "main": "build.ps1",
  "scripts": {
    "test": "test.ps1"
  },
  "author": "",
  "license": "",
  "devDependencies": {
    "bower": "^1.8.0",
    "eslint": "^3.14.1",
    "gulp": "1.*",
    "jest": "^18.1.0"
  }
}