从使用 Parcel bundler 的项目中删除几个文件后，命令parcel ./index.html开始输出以下错误：
Cannot read property 'type' of undefined
at Bundler.createBundleTree (<project_root>/node_modules/parcel-bundler/src/Bundler.js:654:54)
at Bundler.createBundleTree (<project_root>/node_modules/parcel-bundler/src/Bundler.js:721:12)
at Bundler.createBundleTree (<project_root>/node_modules/parcel-bundler/src/Bundler.js:721:12)
at Bundler.createBundleTree (<project_root>/node_modules/parcel-bundler/src/Bundler.js:721:12)
at Bundler.createBundleTree (<project_root>/node_modules/parcel-bundler/src/Bundler.js:721:12)
at Bundler.createBundleTree (<project_root>/node_modules/parcel-bundler/src/Bundler.js:721:12)
at Bundler.bundle (<project_root>/node_modules/parcel-bundler/src/Bundler.js:298:14)
at <anonymous>
at process._tickCallback (internal/process/next_tick.js:189:7)