Angular 7找不到“ Ey”的NgModule元数据

Question

当我使用ng build --prod构建我的角度应用程序时，尝试访问网站时出现以下错误

main.10b5ebb6b9978e58598c.js:1 Uncaught Error: No NgModule metadata found for 'Ey'.
    at t.resolve (main.10b5ebb6b9978e58598c.js:1)
    at t.getNgModuleMetadata (main.10b5ebb6b9978e58598c.js:1)
    at t._loadModules (main.10b5ebb6b9978e58598c.js:1)
    at t._compileModuleAndComponents (main.10b5ebb6b9978e58598c.js:1)
    at t.compileModuleAsync (main.10b5ebb6b9978e58598c.js:1)
    at t.compileModuleAsync (main.10b5ebb6b9978e58598c.js:1)
    at main.10b5ebb6b9978e58598c.js:1
    at t.bootstrapModule (main.10b5ebb6b9978e58598c.js:1)
    at Object.zUnb (main.10b5ebb6b9978e58598c.js:1)
    at p (runtime.a66f828dca56eeb90e02.js:1)

js文件中的错误行：

else _y().bootstrapModule(Ey)}},[[2,0]]]);