Chrome控制台-Uncaught(inpromise)TypeError:this.enginesisnotiterable

当我在 localhost:4200 上加载应用程序文件时，此错误出现在 chrome 控制台中。我无法弄清楚这意味着什么。如何在我的代码中找出此错误的来源？

Uncaught (in promise) TypeError: this.engines is not iterable
    at E.updateSocialMedia (content.js:48)
    at new E (content.js:48)
    at Function.start (content.js:48)
    at Function.main (content.js:48)

Uncaught (in promise) TypeError: this.engines is not iterable
    at E.updateSocialMedia (content.js:48)
    at new E (content.js:48)
    at Function.start (content.js:48)
    at Function.main (content.js:48)

回答