[Slice tool] How to select all slices in one shot

And here is bonus script for selecting slices, which overlap with rectangular selection. First select rectangular selection tool and make a selection. Then run the script.
 

#target photoshop

var s2t = stringIDToTypeID;
var c2t = charIDToTypeID;

// Get current rectangle selection bounds
var currentSelection = getCurrentSelectionBounds();

if (currentSelection) {
    // Switch to Slice Select Tool
    selectSliceSelectTool();

    // Get all slices from document
    var slices = getAllSlices();

    if (slices.length > 0) {
        // Select slices that overlap with the rectangle selection
        selectOverlappingSlices(slices, currentSelection);
    }

    // Clear the original rectangle selection
    clearSelection();
}

// ------------------------------------------------------------
// Gets the bounds of the current selection
function getCurrentSelectionBounds() {
    try {
        var desc = new ActionDescriptor();
        var ref = new ActionReference();
        ref.putProperty(s2t('property'), s2t('selection'));
        ref.putEnumerated(s2t('document'), s2t('ordinal'), s2t('targetEnum'));
        desc.putReference(s2t('null'), ref);

        var selectionDesc = executeAction(s2t('get'), desc, DialogModes.NO);
        var selectionBounds = selectionDesc.getObjectValue(s2t('selection'));

        if (!selectionBounds.hasKey(s2t('top'))) return null;

        return {
            left: selectionBounds.getDouble(s2t('left')),
            top: selectionBounds.getDouble(s2t('top')),
            right: selectionBounds.getDouble(s2t('right')),
            bottom: selectionBounds.getDouble(s2t('bottom'))
        };
    } catch(e) {
        return null;
    }
}

// ------------------------------------------------------------
// Switches to the Slice Select Tool
function selectSliceSelectTool() {
    try {
        var desc = new ActionDescriptor();
        var ref = new ActionReference();
        ref.putClass(s2t('sliceSelectTool'));
        desc.putReference(s2t('null'), ref);
        executeAction(s2t('select'), desc, DialogModes.NO);
    } catch(e) {
        // Tool may already be active - ignore error
    }
}

// ------------------------------------------------------------
// Retrieves all slices from the active document
function getAllSlices() {
    var slices = [];

    try {
        // Get document descriptor
        var docRef = new ActionReference();
        docRef.putEnumerated(s2t('document'), s2t('ordinal'), s2t('targetEnum'));
        var docDescriptor = executeActionGet(docRef);

        // Get slices list from document
        var slicesDescriptors = docDescriptor
            .getObjectValue(s2t('slices'))
            .getList(s2t('slices'));

        // Iterate through all slices
        for (var i = 0; i < slicesDescriptors.count; i++) {
            var currentSlice = slicesDescriptors.getObjectValue(i);
            var sliceBounds = currentSlice.getObjectValue(s2t('bounds'));

            // Get bounds as integers (Photoshop stores slice coordinates as integers)
            var left = sliceBounds.getInteger(s2t('left'));
            var top = sliceBounds.getInteger(s2t('top'));
            var right = sliceBounds.getInteger(s2t('right'));
            var bottom = sliceBounds.getInteger(s2t('bottom'));

            // Get optional name (use default if not present)
            var name = "Slice " + i;
            if (currentSlice.hasKey(s2t('name'))) {
                name = currentSlice.getString(s2t('name'));
            }

            // Get slice ID
            var sliceId = currentSlice.getInteger(s2t('sliceID'));

            slices.push({
                index: i,
                id: sliceId,
                name: name,
                left: left,
                top: top,
                right: right,
                bottom: bottom
            });
        }
    } catch(e) {
        // Silently fail - no slices found
    }

    return slices;
}

// ------------------------------------------------------------
// Checks if two rectangles overlap (partial or full)
function rectsOverlap(rect1, rect2) {
    return !(rect1.right <= rect2.left || 
             rect1.left >= rect2.right || 
             rect1.bottom <= rect2.top || 
             rect1.top >= rect2.bottom);
}

// ------------------------------------------------------------
// Selects slices that overlap with the given selection bounds
function selectOverlappingSlices(slices, selectionBounds) {
    // Find slices that overlap with the selection
    var overlappingSlices = [];
    for (var i = 0; i < slices.length; i++) {
        var slice = slices[i];
        var sliceBounds = {
            left: slice.left,
            top: slice.top,
            right: slice.right,
            bottom: slice.bottom
        };

        if (rectsOverlap(sliceBounds, selectionBounds)) {
            overlappingSlices.push(slice);
        }
    }

    // Select overlapping slices
    for (var j = 0; j < overlappingSlices.length; j++) {
        var slice = overlappingSlices[j];

        // Calculate center point of the slice (click position)
        var x = (slice.left + slice.right) / 2;
        var y = (slice.top + slice.bottom) / 2;

        // Simulate click on slice
        var desc = new ActionDescriptor();
        var refSel = new ActionReference();
        refSel.putClass(s2t('slice'));
        desc.putReference(c2t('null'), refSel);

        var pointDesc = new ActionDescriptor();
        pointDesc.putUnitDouble(c2t('Hrzn'), c2t('#Pxl'), x);
        pointDesc.putUnitDouble(c2t('Vrtc'), c2t('#Pxl'), y);
        desc.putObject(c2t('At  '), c2t('Pnt '), pointDesc);

        // First slice = normal select, subsequent slices = SHIFT+click (add to selection)
        desc.putBoolean(s2t('addToSelection'), j !== 0);

        executeAction(c2t('slct'), desc, DialogModes.NO);
    }
}

// ------------------------------------------------------------
// Clears the current selection (deselect all)
function clearSelection() {
    try {
        var desc = new ActionDescriptor();
        var ref = new ActionReference();
        ref.putProperty(s2t('channel'), s2t('selection'));
        desc.putReference(s2t('null'), ref);
        desc.putEnumerated(s2t('to'), s2t('ordinal'), s2t('none'));
        executeAction(s2t('set'), desc, DialogModes.NO);
    } catch(e) {
        // Ignore errors if no selection to clear
    }
}

Hello, thank you for your response. Unfortunately from what I understood, you just provided me a solution that I already wrote about in my post: "Something similar can be obtained in the new version of Photoshop if you use the Slice Tool Selection, hold Shift and click in each slice (which is taking a lot of time).".

What I would like to know is if I can make this process faster or bypass it, because with a lot of slices it takes a lot of time to select all of them.

Thank you!