Use enviroment variables in yarn package.json - heroku

Question

I want to pull from a private package hosted on bitbucket. Since SSH is not an option for my deploy setup, I want to access the repo using the Application Password.
So my entry in the package JSON looks like this:
"dependencies": {
"#companyName/repository": "git+https://${$BITBUCKET_USER}:${BITBUCKET_APP_PASSWORD}#bitbucket.org/company name/repository.git",
Coding username and password hard into the repo URL works fine but when I perform yarn install as above, the environment variables are not replaced by its values.
Is there any way to use environment variables like this?

Answer 1

You can write a preinstall hook that updates package.json with values from the environment. Luckily the order of lifecycle hooks work as prescribed using yarn.
{
"name": "njs",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"test": "echo \"Error: no test specified\" && exit 1",
"preinstall": "node preinstall.js"
},
"dependencies": {
"#companyName/repository": "git+https://${$BITBUCKET_USER}:${BITBUCKET_APP_PASSWORD}#bitbucket.org/companyName/repository.git"
},
"author": "",
"license": "ISC"
}
preinstall.js example:
const package = require('./package.json');
const fs = require('fs');
const {BITBUCKET_USER = 'test', BITBUCKET_APP_PASSWORD='test'} = process.env;
package.dependencies["#companyName/repository"] = package.dependencies["#companyName/repository"]
.replace("${$BITBUCKET_USER}", BITBUCKET_USER)
.replace("${BITBUCKET_APP_PASSWORD}", BITBUCKET_APP_PASSWORD);
fs.writeFileSync('package.json', JSON.stringify(package, null, 4));
Bonus:
How you choose to replace environment variables in preinstall.js is left to your good judgment. Yes, you can totally use ES6 template tags.