how to create a js prototype class in external file-Collection of common programming errors

To set log on the Logger instance to an empty array, use this.log = [], not var log. The latter creates a private variable, which you can’t access outside the function.

Also, Logger.log means: access the log property on the Logger function. Here you want the instance instead, so use this.log (like you did in ReadLog).

Originally posted 2013-11-09 19:43:02.