use electron-packager './out/aTouchAway Launcher-darwin-x64/aTouchAway Launcher.app' --platform=mas --arch=x64 --icon='./src/favicon.icns' --out=./out to package mas app. Cannot use electron-forge make cause it generate darwin file instead of mas. Use electron-forge make to generage .dmg file

Then inside ./out/project name/project.app file, add

<plist version="1.0">
<dict>
  ...
  <key>ElectronTeamID</key>
  <string>TEAM_ID</string>
</dict>
</plist>

to Info.plist. Change the <key>CFBundleIdentifier</key> to correct Bundle ID.

Create chile.plist:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>com.apple.security.app-sandbox</key>
    <true/>
    <key>com.apple.security.inherit</key>
    <true/>
  </dict>
</plist>

Create parent.plist:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>com.apple.security.app-sandbox</key>
    <true/>
    <key>com.apple.security.application-groups</key>
    <string>TEAM_ID.your.bundle.id</string>
  </dict>
</plist>

change the TEAM_ID.your.bundle.id and add needed permissions according to Apple’s Enabling App Sandbox

Create a bash file:

#!/bin/bash

# Name of your app.
APP="YourApp"
# The path of your app to sign.
APP_PATH="/path/to/YourApp.app"
# The path to the location you want to put the signed package.
RESULT_PATH="~/Desktop/$APP.pkg"
# The name of certificates you requested.
APP_KEY="3rd Party Mac Developer Application: Company Name (APPIDENTITY)"
INSTALLER_KEY="3rd Party Mac Developer Installer: Company Name (APPIDENTITY)"
# The path of your plist files.
CHILD_PLIST="/path/to/child.plist"
PARENT_PLIST="/path/to/parent.plist"

FRAMEWORKS_PATH="$APP_PATH/Contents/Frameworks"

codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$FRAMEWORKS_PATH/Electron Framework.framework/Versions/A/Electron Framework"
codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$FRAMEWORKS_PATH/Electron Framework.framework/Versions/A/Libraries/libffmpeg.dylib"
codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$FRAMEWORKS_PATH/Electron Framework.framework/Versions/A/Libraries/libnode.dylib"
codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$FRAMEWORKS_PATH/Electron Framework.framework"
codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$FRAMEWORKS_PATH/$APP Helper.app/Contents/MacOS/$APP Helper"
codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$FRAMEWORKS_PATH/$APP Helper.app/"
codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$FRAMEWORKS_PATH/$APP Helper EH.app/Contents/MacOS/$APP Helper EH"
codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$FRAMEWORKS_PATH/$APP Helper EH.app/"
codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$FRAMEWORKS_PATH/$APP Helper NP.app/Contents/MacOS/$APP Helper NP"
codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$FRAMEWORKS_PATH/$APP Helper NP.app/"
codesign -s "$APP_KEY" -f --entitlements "$CHILD_PLIST" "$APP_PATH/Contents/MacOS/$APP"
codesign -s "$APP_KEY" -f --entitlements "$PARENT_PLIST" "$APP_PATH"

productbuild --component "$APP_PATH" /Applications --sign "$INSTALLER_KEY" "$RESULT_PATH"

(add --deep to the end of codesign if needed)

Run sign.sh file.

Use Application Loader to upload your file.