Copy text directly from Photoshop text layer.

/*****************************************************************
 *
 * Copy Layer text 1.0 - by Praveen Vijayan! - http://www.decodize.com/
 *
 * Compatibility above Photoshop CS6
 *
 * Licensed under the Creative Commons Attribution 2.5 License - http://creativecommons.org/licenses/by/2.5/
 * 
 *****************************************************************/
 
if(app.activeDocument.activeLayer.kind ==  LayerKind.TEXT){
    const keyTextData         = app.charIDToTypeID('TxtD');
    const ktextToClipboardStr = app.stringIDToTypeID( "textToClipboard" );
    var textStrDesc = new ActionDescriptor();
    textStrDesc.putString( keyTextData, app.activeDocument.activeLayer.textItem.contents );
    executeAction( ktextToClipboardStr, textStrDesc, DialogModes.NO );
 }