Difference between npm install, npm install --save and npm install --save-dev

npm install X:

• will install the X package into the node_modules directory
• will not modify package.json
• X is not automatically installed when running the npm install command afterwards

npm install X –save:

• will install the X package into the node_modules directory

• X will be added under the dependencies property of package.json

• After running the npm install command, X will be automatically installed in the node_modules directory

• After running npm install 
  –production or specifying the value of the NODE_ENV variable as production, msbuild will be automatically installed in the node_modules directory

npm install X –save-dev:

• will install the X package into the node_modules directory

• X will be added under the devDependencies property of package.json

• After running the npm install command, X will be automatically installed in the node_modules directory

• After running npm install 
  –production or specifying the value of the NODE_ENV variable as production, X will not be automatically installed in the node_modules directory

Principles of use:

Use --save for packages that need to be used at runtime, otherwise use --save-dev.

 

Taken from: https://blog.csdn.net/qq_30378229/article/details/78463930