Delete all the channels faster

Question

Hi,
I use the activeDocument.channels.removeAll() function for deleting all the channels, it works well but can be long.
I have a 6K PSD file with 12 extra channels and it takes 2 min to remove them all.
I'm looking for a way to delete all the channels faster.
I tried with actions but I don't achieve to speed up this step.
Is it possible to delete all the channels like the "Delete Hidden Layers" action which is quickly even with a huge PSD file containing many layers ? Or anything else ? If you have any idea or solution.
Thanks

Answer 1

The code below uses the Action Manager API to remove alpha and spot channels from a document. It should be faster than the DOM and as fast as possible with a script.
function deleteAlphaAndSpotChannels(){
     function isAlphaOrSpotChannel(){
     var ref = new ActionReference();
     ref.putEnumerated( charIDToTypeID("Chnl"), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") );
     return executeActionGet(ref).hasKey( stringIDToTypeID('ID') );
     function deleteChannelByIndex( idx ){
          var desc = new ActionDescriptor();
               var ref = new ActionReference();
               ref.putIndex(charIDToTypeID( "Chnl" ), idx )
          desc.putReference( charIDToTypeID( "null" ), ref );
          executeAction( charIDToTypeID( "Dlt " ), desc, DialogModes.NO );
     function getNumberOfChannels(){     
          var ref = new ActionReference();
          ref.putEnumerated( charIDToTypeID("Dcmn"), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") );
          return executeActionGet(ref).getInteger( stringIDToTypeID('numberOfChannels'))// does not count layer masks
     function numberOfComponentChannels(){     
          var ref = new ActionReference();
          ref.putEnumerated( charIDToTypeID("Dcmn"), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") );
          var mode = typeIDToStringID( executeActionGet( ref ).getEnumerationValue( stringIDToTypeID('mode') ) );
          var numberOfComponentChannels = 4;// set default for CMYK
          switch ( mode ){
               case "RGBColor":
                    numberOfComponentChannels = 3;
                    break;
               case "labColor":
                    numberOfComponentChannels = 3;
                    break;
               case "grayScale":
                    numberOfComponentChannels = 1;
                    break;
          return numberOfComponentChannels;
     while( getNumberOfChannels() > numberOfComponentChannels() ){
          makeChannelActiveByIndex( getNumberOfChannels(), false );
          if( isAlphaOrSpotChannel() ){
               deleteChannelByIndex( getNumberOfChannels() );
     function makeChannelActiveByIndex( idx, visible ){
          var desc = new ActionDescriptor();
               var ref = new ActionReference();
               ref.putIndex(charIDToTypeID( "Chnl" ), idx)
               desc.putReference( charIDToTypeID( "null" ), ref );
               desc.putBoolean( charIDToTypeID( "MkVs" ), visible );
          executeAction( charIDToTypeID( "slct" ), desc, DialogModes.NO );
deleteAlphaAndSpotChannels();