Add or remove items from the Finder sidebar

I use mysides (installed via Homebrew) to automate use of my sidebar, which I use constantly. Mysides is quite simple and offers 3 functions: add, remove, and list. My script is a template which allows me to quickly add specified folders to the sidebar, but I can't get it to work removing folders from the sidebar.
Can you help me fix it? The add function is working properly. I discovered that the paths needed the spaces replaced with "%20", so that is working properly.
The template properties are path and user enum (add/remove).
Error when I try to remove an item: Cannot get item at index 0. Number of items is: 0
(Sidebar line 5)

const mySides = '/usr/local/bin/mysides';

// Function to determine if the selected path is a directory or file
function getSelectedFolderPath() {
    const fullPath = decodeURIComponent(sf.appleScript.finder.selection.getItem(0).asItem.path);
    const isDirectory = fullPath.endsWith('/'); // Basic check: a directory might end with a '/'
    
    if (isDirectory) {
        return fullPath; // Return the folder path directly
    } else {
        return fullPath.split('/').slice(0, -1).join('/'); // Return the parent directory if it's a file
    }
}

// Function to URL-encode the path
function encodePath(path) {
    return encodeURI(path).replace(/#/g, '%23').replace(/ /g, '%20');
}

// Function to extract the folder name from the path
function getFolderName(path) {
    return path.split('/').slice(-1)[0]; // Get the last part of the path
}

// Get the folder path from the event props or use the selected folder in Finder
let folderPath = event.props.folderPath;
if (folderPath === "SelectedFolder") {
    folderPath = getSelectedFolderPath();
}

const {change} = event.props;

// Prepare the folder name and URL-encoded path
const folderName = getFolderName(folderPath);
const encodedPath = encodePath(folderPath);
const mysidesCommand = `mysides "${change}" "${folderName}" "file://${encodedPath}"`;

// Log the command to verify it's correct
// log(`Command to be executed: ${mysidesCommand}`);

// Run the command in the background
sf.engine.runInBackground(() => {
    sf.system.exec({
        commandLine: mysidesCommand,
        executionMode: 'Background',
    });
});