How to keep version DRY for both node.js and docker - node.js

Question

I'm building a set of microservices that are run on Docker and orchestrated with Kubernetes. I'm building the services in Node.js and so for each service I have a package.json file that has a version. I'd like to use this version when building my docker images, and to keep the build command simple I'd like to have it be a script in package.json. However, I want to keep the version number DRY (i.e. avoid spreading the version number throughout the package.json file, or having any other copies). For example, if I have the following package.json, how could I reference the version in the script to avoid repeating it?
{
"name": "sample-service",
"version": "1.0.0",
"description": "Sample service",
"dependencies": {
...
},
"scripts": {
"docker": "docker build -t prefix/image-name:$version ."
}
}
Obviously, using $version in the tag there doesn't work so is there another way? Just in case it makes a difference, I'm using yarn rather than npm.

Answer 1

Yes First get the version of package.json
Then export the version to the variable so you can access it as a variable.
Here is your package.json
{
"name": "sample-service",
"version": "1.0.0",
"description": "Sample service",
"dependencies": {
},
"scripts": {
"docker": "export version=$(node -e \"console.log(require('./package.json').version)\") || set version=$(node -e \"console.log(require('./package.json').version)\") ; echo version is: $version; docker build -t prefix/image-name:$version ." }
}
If you run this you will get some thing like