process only if the worksheetname is '*' for all

Public/Import-Excel.ps1

@@ -235,8 +235,14 @@
                                     #    Write-Verbose "Import cell '$($Worksheet.Cells[$R, $P.Column].Address)' with property name '$($p.Value)' and value '$($Worksheet.Cells[$R, $P.Column].Value)'."
                                 }
                             }
+
+                            if ($WorksheetName -eq '*') {
                                 $xlBook["$targetSheetname"] += [PSCustomObject]$NewRow
                             }
+                            else {
+                                [PSCustomObject]$NewRow
+                            }
+                        }
                         #endregion
                     }
                 }
@@ -247,6 +253,8 @@
                 # $EndColumn = 0
                 if ($Path) { $stream.close(); $ExcelPackage.Dispose() }
 
+                if ($WorksheetName -eq '*') {
+
                     if ($Raw) {
                         foreach ($entry in $xlbook.GetEnumerator()) {
                             $entry.Value
@@ -262,3 +270,4 @@
             }
         }
     }
+}

__tests__/ImportExcelTests/ImportExcelTiming.tests.ps1

@@ -0,0 +1,12 @@
+Import-Module $PSScriptRoot\..\..\ImportExcel.psd1 -Force
+
+Describe "Tests Import-Excel Timings" -Tag Timing {
+    It "Should read the 20k xlsx in -le 2100 milliseconds" {
+        $timer = Measure-Command {
+            $data = Import-Excel $PSScriptRoot\TimingRows20k.xlsx
+        }
+
+        $timer.TotalMilliseconds | Should -BeLessOrEqual 2100        
+        $data.Count | Should -Be 19999
+    }
+}