Sometimes it is necessary to differentiate between packages from production and development environments to determine which base url or other variables you need to useMethod 1:

//windows System:
"builddev": "set NODE_ENV=dev&&vue-cli-service build",
"buildprod": "set NODE_ENV=prod&&vue-cli-service build",

//mac System:
"builddev": "export NODE_ENV=dev&&vue-cli-service build",
"buildprod": "export NODE_ENV=prod&&vue-cli-service build",

Method 2:
First install the dependencies: NPM install –save-dev cross-env
Then configure compatible Windows and MAC environments

"builddev": "cross-env NODE_ENV=dev vue-cli-service build",
"buildprod": "cross-env NODE_ENV=prod vue-cli-service build",

Finally, in the JS code, the corresponding value can be obtained through: process.env.node_env, which is used to judge the environment:
baseurl:process.env.NODE_ENV===’prod’?’http://prod.api.com’:’http://test.api.com’
console.log(process.env);// {BASE_URL: “”, NODE_ENV:” prod “}

Ps: The vUE – CLi is used here to configure NODE_ENV, other projects may be to configure WEBPACK_ENV, directly replace, then console. Log (process.env) to see the environment