Let’s get modular

Now let’s use your newly found knowledge about modules.

You will now create a new module and also use some of NodeJS’s built-in modules. The module should be able to return a list of all the rows in all the files in a specified folder. Your module should be able to do that Synchronously and Asynchronously.

Your module should:

• find all the files in a folder
• read the contents of each file in the folder
• find each row in each file
• then append each row to a list
• return the list that contains all the lines off all the files.

For example:

• if there are 3 files in the folder
• and each file has 3 rows
• your modules should return a list containing 9 rows

Use the built in node module called fs - it stands for File System. The fs module handles accessing files from Node.JS.

You should use these 2 function calls from the fs module in your module:

• To get files in the folder: readdirSync
• To get the data in the files: readFileSync

You will need to pass in the encoding of utf8 as an option parameter to readFileSync otherwise a buffer will be returned instead of the string value.

You can read more about the fs module at the Node API documentation.

The module should be in a file called:

• read-folder.js
• expose 2 methods with parameters:
  • linesInFiles which takes folderName as a parameter and returns an list

  • linesInFilesAsync which takes two parameters folderName and callback - the callback should return 2 parameters err & files. Calling it should look like this:

    linesInFilesAsync('/dir/name', function(err, files){ });

• use this folder as input: ./files/week1