Exporting an AI Symbol Library

thank you so much everyone. I'll give this a try. 

Hmm. It's an innocuous line, so I presume that the problem is with reading the file's name.  What about changing line 3 to

var doc1 = app.activeDocument;

So the script will look like

var file1 = File.openDialog("Open Symbol Library File");
app.open(file1);
var doc1 = app.activeDocument;
var y = 0, x = 0, row = 1;
for (var i = 0; i < doc1.symbols.length; i++) {
    symbolItem1 = doc1.symbolItems.add(doc1.symbols[i]);
    symbolItem1.left = x, symbolItem1.top = y;
    symbolItem1.width = 50, symbolItem1.height = 50;
    symbolItem1.selected = true;
    if (i < (10 * row) - 1) {
        x += 50;
    }  else {
        x = 0;
        y -= 50;
        row++;
    }
}
app.copy();
var doc2 = app.documents.add();
app.paste();
for (var k = 0; k < doc2.symbolItems.length; k++){
    doc2.artboards.add(doc2.symbolItems[k].visibleBounds);
}
doc2.artboards[0].remove();
doc1.close(SaveOptions.DONOTSAVECHANGES);

@Kurt Gold  Thanks.  That should make the script straightforward.  (I cannot test it though.)

var file1 = File.openDialog("Open Symbol Library File");
app.open(file1);
var doc1 = app.documents[file1.displayName];
var y = 0, x = 0, row = 1;
for (var i = 0; i < doc1.symbols.length; i++) {
    symbolItem1 = doc1.symbolItems.add(doc1.symbols[i]);
    symbolItem1.left = x, symbolItem1.top = y;
    symbolItem1.width = 50, symbolItem1.height = 50;
    symbolItem1.selected = true;
    if (i < (10 * row) - 1) {
        x += 50;
    }  else {
        x = 0;
        y -= 50;
        row++;
    }
}
app.copy();
var doc2 = app.documents.add();
app.paste();
for (var k = 0; k < doc2.symbolItems.length; k++){
    doc2.artboards.add(doc2.symbolItems[k].visibleBounds);
}
doc2.artboards[0].remove();
doc1.close(SaveOptions.DONOTSAVECHANGES);

so nice! here the latest version with some nice updates 😉 

added little options:
- for scaling (sadly just for plain paths) 
- to have a bit margins between the artboards
- named artboards after symbolnames with number indicator infront (for easy export with nice names ;)) 

// Initialize variables
var doc1 = null;

// Conversion functions - 1:1 since Illustrator uses 72ppi where 1pt = 1px
function pxToPt(px) { return px; }
function ptToPx(pt) { return pt; }

// Check if any document is open
if (app.documents.length > 0) {
    doc1 = app.activeDocument;
}

// Create dialog window
var dialog = new Window("dialog", "Symbol Export Settings");
dialog.orientation = "column";

// Add file selection group
var fileGroup = dialog.add("panel", undefined, "Source File");
fileGroup.orientation = "column";
fileGroup.alignChildren = "left";

var useCurrentRb = fileGroup.add("radiobutton", undefined, "Use Current Document");
var chooseFileRb = fileGroup.add("radiobutton", undefined, "Choose AI File");

// Set initial state based on document availability
if (doc1 === null) {
    useCurrentRb.enabled = false;
    chooseFileRb.value = true;
} else {
    useCurrentRb.value = true;
    useCurrentRb.enabled = true;
}

var chooseGroup = fileGroup.add("group");
var filePathText = chooseGroup.add("edittext", undefined, "");
filePathText.preferredSize.width = 200;
var chooseBtn = chooseGroup.add("button", undefined, "Browse...");

// Set initial state of file selection controls
filePathText.enabled = (doc1 === null);
chooseBtn.enabled = (doc1 === null);

// Enable/disable file selection based on radio button
chooseFileRb.onClick = function() {
    filePathText.enabled = chooseFileRb.value;
    chooseBtn.enabled = chooseFileRb.value;
}
useCurrentRb.onClick = function() {
    filePathText.enabled = false;
    chooseBtn.enabled = false;
}

// Browse button functionality
chooseBtn.onClick = function() {
    var file = File.openDialog("Select Illustrator File", "*.ai");
    if (file) {
        filePathText.text = file.fsName;
        // Open file and update symbol list
        try {
            var tempDoc = app.open(file);
            updateSymbolList(tempDoc);
            tempDoc.close(SaveOptions.DONOTSAVECHANGES);
        } catch(e) {
            alert("Could not open file: " + e);
        }
    }
}

// Add symbol size input (now in pixels)
var sizeGroup = dialog.add("group");
sizeGroup.add("statictext", undefined, "Symbol Size (px):");
var symbolSizeInput = sizeGroup.add("edittext", undefined, "64"); // Default 64px instead of 50pt
symbolSizeInput.characters = 6;
var explainScale = dialog.add("group");
explainScale.add("statictext", undefined, "(!!! needs plain Paths, NO STROCK or EFFECT SCALEING !!!");
// Add margin input (now in pixels)
var marginGroup = dialog.add("group");
marginGroup.add("statictext", undefined, "Margin (px):");
var marginInput = marginGroup.add("edittext", undefined, "24"); // Default 24px instead of 20pt
marginInput.characters = 6;

// Add symbol selection list
var listGroup = dialog.add("group");
listGroup.orientation = "column";
listGroup.alignChildren = "fill";
listGroup.add("statictext", undefined, "Select Symbols to Export:");

// Create selection list
var symbolList = listGroup.add("listbox", undefined, [], {multiselect: true});
symbolList.preferredSize.width = 300;
symbolList.preferredSize.height = 200;

// Function to populate symbol list
function updateSymbolList(sourceDoc) {
    symbolList.removeAll();  // Clear existing items
    for (var i = 0; i < sourceDoc.symbols.length; i++) {
        var item = symbolList.add("item", sourceDoc.symbols[i].name);
        item.selected = true;
    }
}

// Initialize list with current document symbols only if we have one
if (doc1 !== null) {
    updateSymbolList(doc1);
}

// Add Select All/None buttons
var selectGroup = dialog.add("group");
var selectAll = selectGroup.add("button", undefined, "Select All");
var selectNone = selectGroup.add("button", undefined, "Select None");

selectAll.onClick = function() {
    for (var i = 0; i < symbolList.items.length; i++) {
        symbolList.items[i].selected = true;
    }
}

selectNone.onClick = function() {
    for (var i = 0; i < symbolList.items.length; i++) {
        symbolList.items[i].selected = false;
    }
}

// Add buttons
var buttons = dialog.add("group");
buttons.add("button", undefined, "OK");
buttons.add("button", undefined, "Cancel");

// Show dialog
if (dialog.show() == 1) { // OK was pressed
    // Get the source document
    var doc1;
    if (chooseFileRb.value) {
        if (filePathText.text) {
            try {
                doc1 = app.open(File(filePathText.text));
            } catch(e) {
                alert("Could not open file: " + e);
                exit();
            }
        } else {
            alert("Please select a file first!");
            exit();
        }
    } else {
        doc1 = app.activeDocument;
    }
    
    // Convert pixel values to points for Illustrator
    var symbolSize = pxToPt(Number(symbolSizeInput.text));
    var margin = pxToPt(Number(marginInput.text));
    
    // Get selected symbols
    var selectedSymbols = [];
    for (var i = 0; i < symbolList.items.length; i++) {
        if (symbolList.items[i].selected) {
            selectedSymbols.push(doc1.symbols[i]);
        }
    }
    
    // Layout only selected symbols (using point values internally)
    var x = 0, y = 0, row = 1;
    for (var i = 0; i < selectedSymbols.length; i++) {
        symbolItem1 = doc1.symbolItems.add(selectedSymbols[i]);
        
        // Get original dimensions
        var originalBounds = symbolItem1.geometricBounds;
        var originalWidth = originalBounds[2] - originalBounds[0];
        var originalHeight = originalBounds[1] - originalBounds[3];
        
        // Calculate scale percentage
        var scalePercentage = (symbolSize / Math.max(originalWidth, originalHeight)) * 100;
        
        // Position first, then scale
        symbolItem1.left = x;
        symbolItem1.top = y;
        
        // Scale with stroke preservation
        symbolItem1.selected = true;
        app.executeMenuCommand('expandStyle');  // Expand appearance first
        app.executeMenuCommand('expandStyle');  // Sometimes needs two passes
        
        // Scale the expanded item
        symbolItem1.resize(
            scalePercentage, // x percentage
            scalePercentage, // y percentage
            true, // transform patterns
            true, // transform gradients
            true, // transform stroke patterns
            true  // transform linewidths
        );
        
        if (i < (10 * row) - 1) {
            x += symbolSize + margin;
        } else {
            x = 0;
            y -= symbolSize + margin;
            row++;
        }
    }

    // Copy to new document
    app.copy();
    // Create new document with same settings as source
    var preset = new DocumentPreset();
    preset.colorMode = doc1.documentColorSpace;
    preset.units = doc1.rulerUnits;
    preset.width = 800;
    preset.height = 600;
    var doc2 = app.documents.addDocument(doc1.documentColorSpace, preset);
    
    // Remove default swatches and symbols (if any)
    while(doc2.symbols.length > 0) {
        doc2.symbols[0].remove();
    }
    
    app.paste();

    // Create artboards from symbols and match names
    for (var k = 0; k < doc2.symbolItems.length; k++){
        var currentSymbolItem = doc2.symbolItems[k];
        // Find matching symbol from selected symbols by comparing names
        var matchingSymbol = null;
        for (var s = 0; s < selectedSymbols.length; s++) {
            if (currentSymbolItem.symbol.name === selectedSymbols[s].name) {
                matchingSymbol = selectedSymbols[s];
                break;
            }
        }
        
        var newArtboard = doc2.artboards.add(currentSymbolItem.visibleBounds);
        if (matchingSymbol) {
            newArtboard.name = (k + 1) + "_" + matchingSymbol.name;
        } else {
            newArtboard.name = (k + 1) + "_unknown";
        }
        
    }
    doc2.artboards[0].remove()

    if (chooseFileRb.value) {
        
        doc1.close(SaveOptions.DONOTSAVECHANGES);
    }
} else {
    // User cancelled
    alert("Export cancelled");
}