When npm install is run with a specified package argument, it installs the package in the existing node_modules directory. npm install (specified package) npm install express Here are some of the more important ones to be aware of. Npm install can be run with different arguments. The details behind how npm resolves dependencies is outside the scope of this article, but the package-lock.json file can help insure the exact tree is installed with subsequent installs. For example, v1 of module C may get installed at the root level while v2 is installed as a nested dependency of module B. The order in which the dependencies are installed dictates this tree structure. In this case, both versions of the same module C are installed in a tree like structure. This can lead to a situation where module A requires v1 of module C and module B requires v2 of module C. Sometimes different packages require different versions of the same module. What's this tree you ask? Remember that npm install downloads a package and any dependencies it relies on. This makes it easier for subsequent installs to use the exact same tree (regardless of intermediate dependency updates). This file describes the exact dependency tree that was installed. Npm install also generates a package-lock.json file. The downloaded modules are placed in a node_modules folder in the same location as package.json. It's important that npm install is run in the same directory as the package.json file. Running npm install without arguments installs modules defined in the dependencies section of the package.json file. npm install (no arguments) npm installīoth of these commands do the same thing. Let's look at some examples in more detail. It's important that npm install is run in the same location as the package.json file.

The package.json file dictates what modules will get installed in the node_modules folder. When run with arguments, npm install downloads specific modules to the node_modules folder. When run without arguments, npm install downloads dependencies defined in a package.json file and generates a node_modules folder with the installed modules. Npm install can be run with or without arguments. Npm install downloads a package and it's dependencies.

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