Vercel Private Git Dependecy in NPM

config_env.js

const fs = require("fs");
const home = process.env.HOME;
const zeitHome = "/vercel";

const configureGit = function (credentials) {
  console.log("Configuring git credentials for zeit");
  credentials.forEach(credential => {
    fs.appendFileSync(
      home + "/.git-credentials",
      "https://" +
        credential.user +
        ":" +
        credential.token +
        "@" +
        credential.host
    );
  });
  fs.writeFileSync(home + "/.gitconfig", "[credential]\n    helper = store");
};

if (home == zeitHome) {
  configureGit([
    {
      user: "<userName>",
      token: process.env.VERCEL_READ_REPO_TOKEN,
      host: "github.com"
    }
  ]);
}