code: function _performNpmInstall(installDirectory, npmOptions, callback) {
      var npmPath = path.resolve(path.dirname(require.resolve("npm")), "..", "bin", "npm-cli.js");
      var args = [npmPath, "install"].concat(npmOptions);
  
      console.log("running npm " + args.slice(1).join(" ") + " in " + installDirectory);
  
      var child = spawn(process.execPath, args, { cwd: installDirectory });
  
      child.on("error", function (err) {
          return callback(err);
      });
  
      var stdout = [];
      child.stdout.addListener("data", function (buffer) {
          stdout.push(buffer);
      });
  
      var stderr = [];
      child.stderr.addListener("data", function (buffer) {
          stderr.push(buffer);
      });
  
      var exitCode = 0;
      child.addListener("exit", function (code) {
          exitCode = code;
      });
  
      child.addListener("close", function () {
          stderr = Buffer.concat(stderr).toString();
          stdout = Buffer.concat(stdout).toString();
          if (exitCode > 0) {
              console.error("npm-stderr: " + stderr);
              return callback(new Error(stderr));
          }
          if (stderr) {
              console.warn("npm-stderr: " + stderr);
          }
          console.log("npm-stdout: " + stdout);
          return callback();
      });
  
      child.stdin.end();
  }
docs: Private function to run "npm install --production" command in the extension directory.
  
  @param {string} installDirectory Directory to remove
  @param {array} npmOptions can contain additional options like `--production` or `--proxy http://127.0.0.1:8888`
  @param {function} callback NodeJS style callback to call after finish