make logger optional so code can be re-used for CLI interface

lib/cli.js

@@ -5,12 +5,9 @@ const parseUsingDOM = require('./services/dom-parser')
 const { createParserError, createAppLogger } = require('./utils')
 
 const parseHTMLString = (html, { verbose }) => {
-  const dev = process.env.NODE_ENV === 'development'
-  const logger = createAppLogger({ dev })
-
-  if (!verbose) {
-    logger.transports.forEach((transport) => (transport.silent = true))
-  }
+  const logger = verbose ?
+    createAppLogger({ dev: true }) :
+    null
 
   try {
     const LDJSONEventData = parseUsingLDJSONData(html, { logger })