What is the difference between npm install and npm run build?

npm install and npm run build are two commands with distinct purposes, both part of npm (Node Package Manager), which is a package manager for Node.js. However, their functionalities and purposes differ significantly.

npm install

The primary function of the npm install command is to install libraries or tools that a project depends on. When you run npm install in a new project, npm inspects the package.json file in the project root directory, downloads all dependencies listed in the file, and installs them in the node_modules folder.

For example, if your package.json file includes dependencies for React, as shown below:

json
{
  "dependencies": {
    "react": "^17.0.1",
    "react-dom": "^17.0.1"
  }
}

Running npm install will download the specified versions of React and ReactDOM to your local project.

npm run build

The npm run build command is typically used to compile or build your project, converting source code into code that can run in a production environment. What this command specifically does depends on the scripts property defined in the package.json file. This often includes minifying files, converting ES6 syntax to more compatible JavaScript syntax, or other build tasks.

For example, a project using the webpack bundling tool might define the following build script in package.json:

json
{
  "scripts": {
    "build": "webpack --config webpack.prod.config.js"
  }
}

Running npm run build will trigger webpack to build the project according to the configuration in webpack.prod.config.js.

Summary

In summary, npm install is used for installing dependencies, while npm run build is used to build the final deployable application based on your project's specific configuration. Both commands play important roles in modern web development workflows.