error while transpiling or minifying: Error: SyntaxError: Unexpected token: punc (.)

[a4xrbj1]

I get the following error when building a new macOS Electron app:

ERROR  electronApp:  error while transpiling or minifying:  Error: SyntaxError: Unexpected token: punc (.)
    at forEach (/Users/andreaswest/Documents/workspace/frontend/node_modules/meteor-desktop/lib/electronApp.js:870:27)
    at Array.forEach (<anonymous>)
    at ElectronApp.transpileAndMinify (/Users/andreaswest/Documents/workspace/frontend/node_modules/meteor-desktop/lib/electronApp.js:860:15)
    at ElectronApp.build (/Users/andreaswest/Documents/workspace/frontend/node_modules/meteor-desktop/lib/electronApp.js:451:13)
    at MeteorDesktop.buildInstaller (/Users/andreaswest/Documents/workspace/frontend/node_modules/meteor-desktop/lib/index.js:115:9)