I am trying to make a script to use in Illustrator for extraction Colors from Gradient & Saving ...

[Dimitri A.L.]

I am trying to make a script to use in Illustrator for extraction Colors from Gradient and Saving them to ColorGroup. Got stuck on Line: 51 "var newSwatch = colorGroup.addSwatch(color);" , can someone help? 
Saying in advance.. I have many alerts which are not needed in script, but I used them in previous steps to debug when ran into issues before and just haven't cleaned it up for now. 

#target illustrator

// Get the active document
var doc = app.activeDocument;

// Prompt user to select a gradient from the document
var gradientName = promptForGradient(doc);

alert("Selected gradientName: " + gradientName); // Display gradientName value

if (gradientName !== null) {
    // Prompt user to enter the number of steps per percentage
    var stepsPerPercentage = promptForStepsPerPercentage();
    alert("Steps per percentage: " + stepsPerPercentage); // Display stepsPerPercentage value

    if (stepsPerPercentage !== null) {
        // Prompt user to enter the color group name
        var colorGroupName = promptForColorGroupName();
        alert("Color group name: " + colorGroupName); // Display colorGroupName value

        if (colorGroupName !== null) {
            // Check if the color group already exists
            var colorGroup = getColorGroupByName(colorGroupName);

            // If the color group doesn't exist, create it
            if (colorGroup === null) {
                colorGroup = doc.swatchGroups.add();
                colorGroup.name = colorGroupName;
            }

            // Get the specified gradient from the document
            var gradient = getGradientByName(gradientName);
            if (gradient) {
                // Extract colors from the gradient at each step
                for (var i = 0; i <= 100; i++) {
                    var rampPoint = i / (100 * stepsPerPercentage);
                    var existingStop = findStopByRampPoint(gradient, rampPoint);

                    // Check if a gradient stop with the same ramp point already exists
                    if (existingStop !== null) {
                        // If a stop already exists, use its color instead of adding a new stop
                        var color = existingStop.color;
                    } else {
                        // If no stop exists, add a new gradient stop and get the color
                        var gradientStop = gradient.gradientStops.add();
                        gradientStop.rampPoint = rampPoint;
                        var color = gradientStop.color;
                    }

                    // Add the color to the color group
                    var newSwatch = colorGroup.addSwatch(color);
                    var r = Math.round(color.red);
                    var g = Math.round(color.green);
                    var b = Math.round(color.blue);
                    newSwatch.name = "R=" + r + " G=" + g + " B=" + b;
                }
            }

            // Save the document with the extracted colors
            var savePath = "~/Desktop/extracted_colors.ai";
            doc.saveAs(new File(savePath));

            // Close the document
            // doc.close(SaveOptions.DONOTSAVECHANGES);
        } else {
            alert("Invalid color group name. Script execution terminated.");
        }
    } else {
        alert("Invalid steps per percentage value. Script execution terminated.");
    }
} else {
    alert("No gradient selected. Script execution terminated.");
}

// Function to prompt user for selecting a gradient
function promptForGradient(doc) {
    var gradientNames = [];
    var numGradients = doc.gradients.length;

    // Populate an array with gradient names
    for (var i = 0; i < numGradients; i++) {
        gradientNames.push(doc.gradients[i].name);
    }

    // Create a dialog box with dropdown menu for gradient selection
    var dialog = new Window("dialog", "Select Gradient");
    var dropdown = dialog.add("dropdownlist", undefined, gradientNames);
    dropdown.selection = 0;

    // Store the selected gradient name
    var selectedGradientName = null;

    // OK button event listener
    dropdown.onChange = function () {
        selectedGradientName = gradientNames[dropdown.selection.index];
    };

    // Add buttons to the dialog box
    var buttonsGroup = dialog.add("group");
    buttonsGroup.alignment = "right";
    buttonsGroup.add("button", undefined, "OK");
    buttonsGroup.add("button", undefined, "Cancel");

    // OK button event listener
    buttonsGroup.children[0].onClick = function () {
        dialog.close(selectedGradientName);
    };

    // Cancel button event listener
    buttonsGroup.children[1].onClick = function () {
        dialog.close(null);
    };

    // Show the dialog box
    dialog.show();

    // Print the selected gradient name
    if (selectedGradientName) {
        alert("Selected gradientName: " + selectedGradientName);
    }

    return selectedGradientName;
}

// Function to prompt user for entering steps per percentage
function promptForStepsPerPercentage() {
    var dialog = new Window("dialog", "Enter Steps Per Percentage");
    dialog.add("statictext", undefined, "Steps per percentage:");
    var inputBox = dialog.add("edittext", undefined, "1");
    inputBox.characters = 5;

    // Store the entered value
    var enteredValue = null;

    // Add buttons to the dialog box
    var buttonsGroup = dialog.add("group");
    buttonsGroup.alignment = "right";
    buttonsGroup.add("button", undefined, "OK");
    buttonsGroup.add("button", undefined, "Cancel");

    // OK button event listener
    buttonsGroup.children[0].onClick = function () {
        var value = parseFloat(inputBox.text);
        if (!isNaN(value) && value > 0) {
            enteredValue = value;
            dialog.close(enteredValue);
        } else {
            alert("Invalid steps per percentage value. Please enter a positive number.");
        }
    };

    // Cancel button event listener
    buttonsGroup.children[1].onClick = function () {
        dialog.close(null);
    };

    // Show the dialog box
    dialog.show();

    // Print the entered value
    if (enteredValue) {
        alert("Entered steps per percentage: " + enteredValue);
    }

    return enteredValue;
}

// Function to prompt user for entering the color group name
function promptForColorGroupName() {
    var dialog = new Window("dialog", "Enter Color Group Name");
    dialog.add("statictext", undefined, "Color group name:");
    var inputBox = dialog.add("edittext", undefined, "Extracted Colors");
    inputBox.characters = 20;

    // Store the entered value
    var enteredValue = null;

    // Add buttons to the dialog box
    var buttonsGroup = dialog.add("group");
    buttonsGroup.alignment = "right";
    buttonsGroup.add("button", undefined, "OK");
    buttonsGroup.add("button", undefined, "Cancel");

    // OK button event listener
    buttonsGroup.children[0].onClick = function () {
        enteredValue = inputBox.text;
        dialog.close(enteredValue);
    };

    // Cancel button event listener
    buttonsGroup.children[1].onClick = function () {
        dialog.close(null);
    };

    // Show the dialog box
    dialog.show();

    // Print the entered value
    if (enteredValue) {
        alert("Entered color group name: " + enteredValue);
    }

    return enteredValue;
}

// Function to retrieve gradient by name
function getGradientByName(name) {
    var numGradients = doc.gradients.length;

    // Iterate through the gradients and find the one with the matching name
    for (var i = 0; i < numGradients; i++) {
        var gradient = doc.gradients[i];
        if (gradient.name === name) {
            return gradient;
        }
    }

    return null;
}

// Function to retrieve color group by name
function getColorGroupByName(name) {
    var numColorGroups = doc.swatchGroups.length;

    // Iterate through the color groups and find the one with the matching name
    for (var i = 0; i < numColorGroups; i++) {
        var colorGroup = doc.swatchGroups[i];
        if (colorGroup.name === name) {
            return colorGroup;
        }
    }

    return null;
}

// Function to find a gradient stop by ramp point
function findStopByRampPoint(gradient, rampPoint) {
    var numStops = gradient.gradientStops.length;

    // Iterate through the gradient stops and find the one with the matching ramp point
    for (var i = 0; i < numStops; i++) {
        var stop = gradient.gradientStops[i];
        if (stop.rampPoint === rampPoint) {
            return stop;
        }
    }

    return null;
}

[femkeblanco]

colorGroup.addSwatch() takes a swatch as an argument, not a color, hence the error. 

[CarlosCanto]

to expand of what femkeblanco said, you would need to add a swatch to the documents first, then you can add that swatch to the swatch group

// Add the color to the color group
var newSwatch = doc.swatches.add();
colorGroup.addSwatch(newSwatch);
//newSwatch.color = color;

[Charu Rajput]

Hi @Dimitri A.L. ,

Try the following action script. The follwoing action will add colors from the selection to the new color group. 

var actionStr = [
    "/version 3",
    "/name [ 5",
    "	5365742031",
    "]",
    "/isOpen 1",
    "/actionCount 1",
    "/action-1 {",
    "	/name [ 9",
    "		416464436f6c6f7273",
    "	]",
    "	/keyIndex 0",
    "	/colorIndex 0",
    "	/isOpen 0",
    "	/eventCount 1",
    "	/event-1 {",
    "		/useRulersIn1stQuadrant 0",
    "		/internalName (ai_plugin_swatches)",
    "		/localizedName [ 8",
    "			5377617463686573",
    "		]",
    "		/isOpen 1",
    "		/isOn 1",
    "		/hasDialog 1",
    "		/showDialog 0",
    "		/parameterCount 1",
    "		/parameter-1 {",
    "			/key 1835363957",
    "			/showInPalette 4294967295",
    "			/type (enumerated)",
    "			/name [ 15",
    "				4e657720436f6c6f722047726f7570",
    "			]",
    "			/value 17",
    "		}",
    "	}",
    "}",
    ""
].join("\n");

var actionFileDestStr = Folder.desktop + "/MyAction.aia";
var actionFile = File(actionFileDestStr);
actionFile.open('w');
actionFile.write(actionStr);
actionFile.close();
app.loadAction(actionFile);
app.doScript("AddColors", "Set 1");
actionFile.remove();
app.unloadAction("Set 1", '');