node.js minimal setup and for what is the package.json?

Question

So i start off with writing my own node.js app and the only thing i want is to include a package for saml.

So i was wondering what is the minimal requirement for my app.

I was just creating a node.js file and then i installed the package by: node install some-saml-passports-package.

I got this warning after installation:

npm WARN enoent ENOENT: no such file or directory, open '.../mynodeapp/package.json'

I removed the package and created a package.json file. Which results in a parsing error because there was no content inside.

I have read that I only need a package.json when I plan to create my own package. Also I read something about local and global installation of package files in npm. Well, i need a bit of clarification for my doing.

What is the use of package.json?
Do I need it when I only want to create a standalone app in node with one dependency to an existing package?
Is it recommended even if I don't need it at all?

Answer 1

There is no minimum requirement for node.js application. The package.json is only required to manage your application for dependencies, module descriptions , handle npm scripts etc. You can install packages without package.json, just don't use the --save flag with npm install. E.g.:

npm install <package_name> - you can still run your node application without any problem. But I will suggest you to add a package.json file and add following:

{
    "name": "<package_name>",
    "version": "<version>", //0.0.1 for starters
    "description": "",
    "main": "<entry point of application>", // example: app.js , index.js etc
    ,
    "author": "<your name>",
    "license": "ISC",
    "dependencies": {}
}

You can create this by adding it manually or just execute npm init in your project root directory and answer some basic questions in console.

Here are some useful links:

npm init

how to use package.json

Answer 2

The minimal file is:

{
}

Now you can start using commands like npm install web3 --save and they will save onto this file.