总是报错, Cannot read property ‘emit’ of undefined;at setTimeout callback function

要怎么调试? 找不到问题源头

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Cannot read property 'emit' of undefined;at setTimeout callback function

TypeError: Cannot read property 'emit' of undefined

at Function.<anonymous> (https://usr/app-service.js:1103:3415)

at Function.<anonymous> (https://lib/WASubContext.js:2:92781)

at https://lib/WASubContext.js:2:99031