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

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"
}
}