(node:57300) UnhandledPromiseRejectionWarning: Error: Can't set headers after they are sent.
    at validateHeader (_http_outgoing.js:491:11)
    at ServerResponse.setHeader (_http_outgoing.js:498:3)

In the Node project, you encountered this error while doing module splitting.
is checked to be package.json deleted

"babel-preset-env": "1.3.2",
"babel-preset-es2015": "6.24.1",
"babel-preset-stage-2": "6.24.1"

These three modules cause these three modules not to be deleted.
is originally required by the server to render the json inside the reference file is relative. Node_modules relative to the root directory, so the items below the root directory are related to modules such as vue, Babel-Polyfill, etc.