Lip: Writing Testable Node.js Code

// lib/redis-click-logger.js

  module.exports = {
    redisClickLogger: async () => {
      const batchSize = getBatchSize();
      // ...
    }
    _getBatchSize: getBatchSize
  }

  function getBatchSize ( defaultBatchSize = 1000 ){
   return process.env.BATCH_SIZE || defaultBatchSize;
  }

Didn't know that LIP stands for Learning In Public, but I kind of like this abbreviation.