Purpose:

package.json : This file is primarily used for managing and documenting metadata about the project, including its names,version,author, dependencies,scripts and other configuration details. It acts as a manifest for the project.

package-lock.json : This file is generated and updated automatically by npm when installing or updating packages. It is used to lock the exact version of dependencies installed in the project, ensuring reproducibility and consistent installations across different environments.

Dependency Specification

package.json : It contains the list of dependencies required for the project, along with their desired version ranges specified using semenatic versioning or specific version numbers.

package-lock.json : It includes the specific resolved versions of all the dependcies, their sub-dependencies, and their exact installation location. It acts as a snapshot of the dependency tree for enusring consistent installation.

Version Control :

package.json : It is typically tracked in version control system like Git and serves as a shared configuration file among project contributors.

package-lock.json : It is also tracked in version control system to ensure consisten dependency installations across different development environments.

Manual Editing :

package.json : Developers manually edit this file to add or remove dependencies, modify scripts ,update version or make other configuration changes.

package-lock.json : It is generally not meant to be manually edited, as it is managed automatically by npm. Manual changes to this file can be lead to inconsistencies or conflicts in dependency resolution.