delete the last three history state

[Mohamed Hameed]

welcome everybody

- I want a code that deletes the last three history state

[c.pfaffenbichler]

DOM appears to offer no Methods for HistoryState so please record the operation with ScriptingListener.plugin yourself. 

[Mohamed Hameed]

@c.pfaffenbichler 

Aha ok sir
You mean that there is no direct command to delete history satate
Is this what you mean sir??

I found this code works to set the last history state
How can I delete the last specified record

var doc = app.activeDocument;  
	doc.activeHistoryState = doc.historyStates[doc.historyStates.length-1]; 

[c.pfaffenbichler]

I found this code works to set the last history state
How can I delete the last specified record

var doc = app.activeDocument;  
	doc.activeHistoryState = doc.historyStates[doc.historyStates.length-1]; 

That code does not delete a HistoryState it selects one (makes it the active one). 

@c.pfaffenbichler 

Aha ok sir
You mean that there is no direct command to delete history satate
Is this what you mean sir??

I mean you should use ScriptingListener.plusing to record deleting the last HistoryState.  

[Mohamed Hameed]

That code does not delete a HistoryState it selects one (makes it the active one). 

Well I know it selects one
But how to delete history when it is activated

There is a way to delete this record

[c.pfaffenbichler]

I have already told you to use ScriptingListener.plugin to record the operation twice.  

Is there a problem with this? 

https://helpx.adobe.com/photoshop/kb/downloadable-plugins-and-content.html

[Mohamed Hameed]

@c.pfaffenbichler 

Sorry bro, I don't know what is the difference between script code
and ScriptingListener. plugin

Or how can I write a line for this

[c.pfaffenbichler]

Please don’t bother asking questions but install ScriptingListener.plugin and use it to record the code for the operation already. (Edit: If the recorded code does not perform as expected then please post it with a clear explanation what happens/fails to happen.) 

I won’t try to explain the difference between Photoshop’s DOM- and AM-code now. 

[Mohamed Hameed]

@c.pfaffenbichler

Very sorry to disturb you
Well, I will do as you tell me
Thank you for your interest and sorry again for the inconvenience sir

[Stephen Marsh]

@Mohamed Hameed 

You can download the plug-in here:

https://helpx.adobe.com/au/photoshop/kb/downloadable-plugins-and-content.html

You should get something like the following to delete the active history state:

var iddelete = stringIDToTypeID( "delete" );
    var desc57 = new ActionDescriptor();
    var idnull = stringIDToTypeID( "null" );
        var ref4 = new ActionReference();
        var idhistoryState = stringIDToTypeID( "historyState" );
        var idcurrentHistoryState = stringIDToTypeID( "currentHistoryState" );
        ref4.putProperty( idhistoryState, idcurrentHistoryState );
    desc57.putReference( idnull, ref4 );
executeAction( iddelete, desc57, DialogModes.NO );

[Stephen Marsh · Accepted solution]

@Mohamed Hameed 

Try the following code, it has not been exhaustively tested, however, it would appear to do what you have requested:

/*
Delete The Last 3 History States.jsx
https://community.adobe.com/t5/photoshop-ecosystem-discussions/delete-the-last-three-history-state/td-p/14022026
v1.0 - 21st August 2023, Stephen Marsh
*/

#target photoshop

var theStateLength = activeDocument.historyStates.length - 1;
if (theStateLength >= 4) {
    // Perform the tasks 3 times
    for (i = 0; i < 3; i++) {
        // Select the last history step
        activeDocument.activeHistoryState = activeDocument.historyStates[activeDocument.historyStates.length - 1];
        // Delete the active history step
        removeHistoryStep();
    }
    alert("The last 3 history states have been deleted!")
} else {
    alert("Script cancelled as there are only 3 or less history states!")
}

function removeHistoryStep() {
    function s2t(s) {
        return app.stringIDToTypeID(s);
    }
    var descriptor = new ActionDescriptor();
    var reference = new ActionReference();
    reference.putProperty(s2t("historyState"), s2t("currentHistoryState"));
    descriptor.putReference(s2t("null"), reference);
    executeAction(s2t("delete"), descriptor, DialogModes.NO);
}

[Mohamed Hameed]

@Stephen Marsh 

Thank you very much for your help
The code has already worked very well
Thank you again sir

[Stephen Marsh]

@Mohamed Hameed 

You're welcome, and it was constructive that you did post the code to select the last snapshot, it shows that you are at least trying.