Yes
No, reproducible on a brand new project.
N/A
System:
OS: macOS 10.14.1
CPU: x64 Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
Binaries:
Node: 10.11.0 - /usr/local/bin/node
Yarn: 1.9.4 - /usr/local/bin/yarn
npm: 6.4.1 - /usr/local/bin/npm
Browsers:
Chrome: 70.0.3538.77
Firefox: 60.0.1
Safari: 12.0.1
npmPackages:
react: ^16.6.1 => 16.6.1
react-dom: ^16.6.1 => 16.6.1
react-scripts: 2.1.1 => 2.1.1
npmGlobalPackages:
create-react-app: Not Found
npm i greenlet)greenlet HOFIn version 1.x of CRA, this was working without any issue. (I still have CRA 1.x deployed in production, I am working on upgrading)
An error occurs: ReferenceError: _Users_sjesso_workspace_greenlet_spread_issue_node_modules_babel_runtime_helpers_esm_objectSpread__WEBPACK_IMPORTED_MODULE_0__ is not defined

I have attached a zip of a basic project that reproduces the problem to this ticket. It is an out-of-the-box CRA with greenlet installed and an example function written. If you change line 38 from return {...{time: Date.now()}}; to return {time: Date.now()}; then the code will run fine.
I removed the node_modules folder to make the zip a reasonable size, so don't forget to npm i before running!
We use greenlet in to make dealing with webworkers easier. In our app, we have a page that needs to load in excess of 50,000 records from an API call for reporting purposes. The data we receive back from the API needs to be massaged into data structures that are easy to work with in our charting library, and this work is done inside of a webworker to avoid blocking the main thread.
seem to work fine for me with npm and yarn.
EDIT: didn't look at console.log closely enough. It did show up.
I am also getting this. I am running the same OS as OP if that makes a difference. Same stack trace as Tony, posted here just in case:

Update: I got around this issue by moving my webworker scripts to /public and referencing them as opposed to using Greenlet.
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