npm-start

View documentation for the original command

$ tldr npm run

npm start [-- <args...>]

--
    This special parameter indicates the end of npm options and the beginning of arguments that should be passed directly to the script being executed. For example, npm start -- --port 8080 would pass --port 8080 to the start script, assuming the script processes such arguments.

npm start is a convenient command provided by Node.js's package manager, npm. It's primarily used to execute the script named "start" defined in the scripts section of a project's package.json file. This command serves as a standardized way to kick off a project, whether it's a web server, a build process, or a development environment. When npm start is run, npm looks for the "start" entry in the scripts object and executes its associated value using a shell. If no "start" script is explicitly defined, npm has a default fallback behavior: it will attempt to run node server.js or node index.js if those files exist in the project's root directory. This makes npm start incredibly versatile, acting as the primary entry point for running most Node.js applications or related development tasks. It streamlines the workflow by abstracting away the underlying commands, allowing developers to remember one simple command to get their project running.

• Reliance on package.json: npm start depends entirely on a package.json file existing in the current or a parent directory, and ideally, having a "start" script defined within its scripts section.
  
• Script-Dependent Behavior: The actual behavior of npm start is determined solely by the command(s) specified in the "start" script. If the script contains errors or invalid commands, npm start will fail accordingly.
  
• Process Management: npm start executes a script, but it does not inherently provide robust process management features (like monitoring, restarting, or daemonizing) out of the box. For production environments, tools like PM2, systemd, or Docker are often used in conjunction with or instead of directly running npm start.
  
• Fallback Logic: While convenient, relying on the default fallback (node server.js or node index.js) can sometimes be less explicit and harder to debug than a clearly defined "start" script.

When you need to pass specific arguments to the underlying script executed by npm start, you must use a double dash (--) after npm start. This signals to npm that all subsequent arguments should be treated as arguments for the script, not for npm itself. For example, if your start script is node server.js, you could run npm start -- --port 3000 to pass --port 3000 to node server.js.

If no "start" script is explicitly defined in your package.json, npm will attempt to execute a default script. Specifically, it looks for index.js or server.js in the project's root directory and tries to run node index.js or node server.js respectively. This fallback provides a simple way to run basic Node.js applications without needing to configure a "start" script, though it's generally recommended to define one for clarity and control.

The npm command-line interface, including the start command, has been an integral part of the Node.js ecosystem since its early days. As Node.js gained popularity, npm emerged as the standard package manager, and its scripts feature, including dedicated shortcuts like start, test, and install, was designed to standardize common project operations. The start command quickly became the de facto way to launch a Node.js application or development server, simplifying project onboarding and execution across different environments and teams. Its evolution has been tied directly to the growth and needs of the Node.js developer community, emphasizing convenience and convention over configuration.

npm-run-script(1), npm-test(1), npm-install(1), package.json(5), node(1)