These are packages written and maintained by other people. You just use their work in your project.

For example

1. Express
2. chalk

You can read more about them on their npm page -

https://www.npmjs.com/package/chalk

Sometimes they are open source as well -

https://github.com/chalk/chalk

Semantic Versioning Format

Every external package is updated incrementally. A specific version looks something like follows -

"chalk": "^5.3.0"

The format is as follows - MAJOR.MINOR.PATCH

• MAJOR - Major version changes indicate significant updates or breaking changes.
• MINOR - Minor version changes signify the addition of new features or improvements in a backward-compatible manner.
• PATCH - Patch version changes include backward-compatible bug fixes or minor improvements that address issues without adding new features or causing breaking changes.

Usage in package.json

• “chalk”: “^5.3.0” - npm will install any version that is compatible with 5.3.0 but less than 6.0.0. This includes versions like 5.3.1, 5.4.0, 5.5.0, etc.
• “chalk”: “5.3.0” - Will install the exact version
• "chalk": "latest" - Will install the latest version