element-desktop/scripts/electron_afterSign.js

const { notarize } = require('electron-notarize');

exports.default = async function(context) {
    const { electronPlatformName, appOutDir } = context;

    if (electronPlatformName === 'darwin') {
        const appName = context.packager.appInfo.productFilename;
        // We get the password from keychain. The keychain stores
        // user IDs too, but apparently altool can't get the user ID
        // from the keychain, so we need to get it from the environment.
        const userId = process.env.NOTARIZE_APPLE_ID;
        if (userId === undefined) {
            throw new Error("User ID not found. Set NOTARIZE_APPLE_ID.");
        }

        console.log("Notarising macOS app. This may be some time.");
        return await notarize({
            appBundleId: 'im.riot.app',
            appPath: `${appOutDir}/${appName}.app`,
            appleId: userId,
            appleIdPassword: '@keychain:NOTARIZE_CREDS',
        });
    }
};