Tally By File Extension CommitStream.js

Tally by File Extension CommitStream.js

function tally(root, prop) {
  if (!root[prop]) root[prop] = 0;
  root[prop]++;
}

function hasItems(array) {
    return array && array.length > 0;
}

function tallyBy(state, key, length) {
    state.summary[key] += length;
}

function tallyByFileExtensions(fileExtensions, array) {
    array.forEach(function(item) {
       var extension =  getFileExtension(item);
       if (extension) tally(fileExtensions, extension);
    });
}

function getFileExtension(item) {
    var lastDot = item.lastIndexOf('.');
    if (lastDot < 0) return false;
    var extension = item.substring(lastDot + 1);
    return extension;
}

fromStream("$et-GitHubCommitReceived")
  .when({
    $init: function() {
      return {
          touched: 0,
          summary: {
              modified: 0,
              added: 0,
              removed: 0
          },
          fileExtensions: {}
      }  
    },
    GitHubCommitReceived: function(s, e) {
        var original = e.data.originalMessage;
        if (!original) return;
        var options = {
            modified : original.modified,
            added : original.added,
            removed : original.removed
        };
        for(var key in options){
            var items = options[key];
            if (hasItems(items)) {
                tallyBy(s, key, items.length);
                tallyByFileExtensions(s.fileExtensions, items);
            }
        }
    }
  });