Starting a New JavaScript Project¶

When working with JavaScript projects using npm, you can install dependencies
locally to your project, similar to how Python virtual environments work.

Local installation ensures that the dependencies are confined to your project
and do not affect the global JavaScript environment.

Creating a New Project¶

A package.json file indicates that the current directory is a JavaScript project.
This file will automatically be generated when you initialize your project.

Initialize Your Project:
First, create a new directory for your project and initialize it with a package.json file.
This file will track your project's dependencies.
```
mkdir my_project  
cd my_project  
npm init -y  
```
* The npm init -y command creates a package.json file with default values.
Install Dependencies Locally:
- Install your project's dependencies locally using the npm install command.
```
npm install <package_name>  
```
- This will install the package in your project's node_modules directory.
- By default, this will install the package only for the current project.
- For example, to install Express.js:
```
npm install express  
```
Using the Local node_modules:
- The locally installed packages are accessible for your project's files
  and can be required or imported as needed.
- Node.js will look in your project's node_modules directory for these packages.

Managing Local Packages¶

package.json
- This file tracks all your local dependencies.
- Ensure that it's included in your version control system.
node_modules
- This directory contains all the locally installed packages.
- It's typically not included in version control (add it to .gitignore).
package-lock.json
- Generated after installations and ensures consistent installs across machines.
- It should be included in version control.

Example `package.json` File¶

After running npm init in your project folder, your package.json might look something like this:

{
  "name": "my_project",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC"
}

After installing dependencies (Express.js in this example), your package.json might look something like this:

{
  "name": "my_project",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^4.17.1"
  },
  "devDependencies": {},
}

`npm init -y` and `package.json`¶

The npm init -y command is a quick way to initialize a new Node.js project with a default package.json file.

The -y flag stands for "yes," and it tells npm to skip the interactive questionnaire and generate a package.json file with default values immediately.

Breakdown of `npm init -y`¶

npm init:
npm init is the standard command used to create a new package.json file for a Node.js project.
When run without flags, npm init prompts the user to answer several questions (like project name, version, description, entry point, etc.) to customize the package.json file.
-y Flag:
The -y flag bypasses these questions and fills in default values automatically.
This is useful for quickly setting up a project without the need for customization at the initial stage.
Generated package.json:
The package.json file created with npm init -y will have standard default values:
- name: The name of the directory.
- version: "1.0.0".
- description: An empty string.
- main: "index.js".
- scripts: An object with a test script.
- keywords: An empty array.
- author: An empty string.
- license: "ISC".

Example¶

Running npm init -y in a directory named my_project will create a package.json that looks something like this:

```json { "name": "my_project", "version": "1.0.0", "description": "", "main": "index.js", "scripts": { "test": "echo \"Error: no test specified\" && exit 1" }, "keywords": [], "author": "", "license": "ISC" }