The setting to identify an SPO/Onprem project for spfx

In file .yo-rc.json, the value of “environment” is either “spo” or “onprem”, it identify your project is on-premises or sharepoint online. If you want to create extension, you have to use “spo”

{
“@microsoft/generator-sharepoint”: {
“version”: “1.4.1”,
“libraryName”: “quantr-express”,
“libraryId”: “1a6a217f-6fb8-44b4-981f-35d0ebe7025b”,
“environment”: “onprem”
}
}