how to return arrays from functions to not cause performance issues

Author: alan-null

good-practices/return.ps1

@@ -0,0 +1,64 @@
+Clear-Host
+$tmpFile = 'd:\temp\tmp.mp4'
+
+function Get-Obj {
+    [byte[]]$payload = [System.IO.File]::ReadAllBytes($tmpFile)
+    $payload
+}
+
+function Get-Wrapped {
+    [byte[]]$payload = [System.IO.File]::ReadAllBytes($tmpFile)
+    @{ wrap = $payload }
+}
+
+function Get-Operator {
+    [byte[]]$payload = [System.IO.File]::ReadAllBytes($tmpFile)
+    ,$payload
+}
+
+function Get-WriteOutput {
+    [byte[]]$payload = [System.IO.File]::ReadAllBytes($tmpFile)
+    Write-Output $payload -NoEnumerate
+}
+
+Measure-Command {
+    [byte[]]$out1 = Get-Obj
+    Write-Host "Size: $($out1.Length)"
+}
+
+Measure-Command {
+    $out2 = Get-Wrapped
+    Write-Host "Size: $($out2.wrap.Length)"
+}
+
+Measure-Command {
+    $out3 = Get-Operator
+    Write-Host "Size: $($out3.Length)"
+}
+
+Measure-Command {
+    $out4 = Get-WriteOutput
+    Write-Host "Size: $($out4.Length)"
+}
+
+# OUTPUT for 6.5 MB file
+
+##### Get-Obj #####
+# Size: 6 439 243
+# TotalSeconds      : 2.4369009
+# TotalMilliseconds : 2436.9009
+
+##### Get-Wrapped #####
+# Size: 6 439 243
+# TotalSeconds      : 0.0087145
+# TotalMilliseconds : 8.7145
+
+##### Get-Operator #####
+# Size: 6 439 243
+# TotalSeconds      : 0.025268
+# TotalMilliseconds : 25.268
+
+##### Get-WriteOutput #####
+# Size: 6 439 243
+# TotalSeconds      : 0.0205171
+# TotalMilliseconds : 20.5171