ng build --prod之后开始出现属性“ [Symbol.iterator]”丢失的错误。”

Question

运行Angular Application时出现此错误。

main-73e1a7066c.js:1 Uncaught TypeError: Cannot read property 'Symbol(Symbol.iterator)' of undefined
at d (main-73e1a7066c.js:1)
at v (main-73e1a7066c.js:1)
at new t (main-73e1a7066c.js:1)
at h (main-73e1a7066c.js:1)
at main-73e1a7066c.js:1
at Io (main-73e1a7066c.js:1)
at main-73e1a7066c.js:1
at new t (main-73e1a7066c.js:1)
at Object.ns [as createNgModuleRef] (main-73e1a7066c.js:1)
at e.create (main-73e1a7066c.js:1)