package.json - How can I reference package version in npm script?

Question

I want to reference my package version in a npm script so I can show current version in the app. Something like

{
  "name": "bla",
  "version": "1.0.0",
  "author": "bla bla",
  "scripts": {
    "build": "node VERSION=<<package.version>> build/build.js"
  }
}

Is there a way to do this?

Answer 1

1) Referencing package version in npm-scripts.

In npm-script's you can reference the version using the variable npm_package_version. For example:

• Using a bash shell (E.g. Linux, macOS):

  {
    ...
    "version": "1.0.0",
    "scripts": {
      "build": "echo $npm_package_version"
    }
  }
  

  Note the $ prefix

• Using Windows (E.g. cmd.exe, Powershell):

  {
    ...
    "version": "1.0.0",
    "scripts": {
      "build": "echo %npm_package_version%"
    }
  }
  

  Note the % prefix and suffix

• Cross platform

  To utilize one syntax cross-platform check out the package cross-var

---

2) Referencing package version in node script.

The package version can also be referenced in your a app/node script (i.e. build.js) as follows:

const VERSION = process.env.npm_package_version;
console.log(VERSION); // --> 1.0.0

---

3) Replacing a placeholder string in a .js file with package version.

Another way to achieve this is to specify a placeholder text string within your JavaScript file. Lets say we have a file named build.js and within that file we have a variable named VERSION declared as follows:

// build.js
const VERSION = '@VERSION@'

As you can see, the placeholder text string is @VERSION@.

You can then install and utilize the package called replace in an npm-script as follows:

{
  ...
  "version": "1.0.0",
  "scripts": {
    "add-version":  "replace -s "@VERSION@" $npm_package_version build/build.js"
  }
}

Running npm run add-version will replace the instance of @VERSION@ with the package version (i.e. 1.0.0), in the file named build.js. This solution will hard-code the npm package version into the resultant file.

Note: The to string in the add-version script (above) currently uses the $ prefix (i.e. $npm_package_version) to access the variable, so this will only run successfully on a bash shell. However, for cross-platform usage you'll need to use cross-var as explained in section one (above). In which case the add-version script can be defined as follows:

{
  ...
  "version": "1.0.0",
  "scripts": {
    "add-version":  "cross-var replace -s "@VERSION@" $npm_package_version build/build.js"
  }
}