Declare Node version for a project

In a Node.js project, versions of Node that a project is compatible with can be declared using the "engines" key within the package.json file. To set a specific Node version (or a range of versions), you'll use the node property inside the engines object.

For example, to specify that your project is compatible with Node version 14.15.1, you would include the following:

{ 
  "engines": { "node": "14.15.1" }
}

If you want to indicate compatibility with various versions, you can use semantic versioning notation. For instance, "node": ">=14.0.0 <15.0.0" means your project is compatible with versions of Node greater than or equal to 14.0.0 but less than 15.0.0. By setting the engines key, you hint to other developers and deployment platforms about which Node versions should be used with your project. Note, however, that unless you use a package manager that enforces this (e.g., Yarn or newer versions of npm), this is primarily advisory and won't prevent the project from running on non-specified versions.