node.js - npm install安装时忘记--save，后来怎么补，难道要重装一次吗

Question

比如我在npm install express时忘记了--save了，现在我想在package.json里写上依赖，难道我要重新npm install express --save吗，感觉应该有另一条补救的语句。。。。

Answer 1

It is also possible to reinstall it. If npm finds that this package has already been installed, it will skip the installation

Answer 2

You just need to write the package into dependency or devDependency in package.json. Because the source files of the package have actually been downloaded to the node_module folder of your project, adding this sentence to package.json is just to ensure that you can install the dependent resources through npm i in the future

Answer 3

Reinstallation is also very fast. You don’t need to download it. You just check it and add the library name to the package file.