code: function installNodeModules(modules, callback) {
      // base case
      if (modules.length <= 0) {
        return callback();
      }
  
      // install one at a time
      const module = modules.pop();
      console.log(`BRANCH SDK: Installing node dependency ${module}`);
  
      const install = `npm install --prefix ./plugins/${SDK} -D ${module}`;
      exec(install, (err, stdout, stderr) => {
        // handle error
        if (err) {
          throw new Error(
            `BRANCH SDK: Failed to install Branch node dependency ${module}. Docs https://goo.gl/GijGKP`
          );
        } else {
          // next module
          installNodeModules(modules, callback);
        }
      });
    }
docs: installs the node modules via npm install one at a time