count-exports.js

var fs = require('q-io/fs');
var q = require('q');


var ignoreNodeDirectory = function(path) {
  return path.indexOf('src/node/') === -1;
};

var EXPORT_REGEXP = /export/g;

fs.listTree('./src', ignoreNodeDirectory).then(function(files) {
  var parsingAllFiles = [];

  files.forEach(function(filepath) {
    if (!/\.js$/.test(filepath)) {
      return;
    }

    parsingAllFiles.push(fs.read(filepath).then(function(content) {
      var match = content.toString().match(EXPORT_REGEXP);
      return {file: filepath, count: match && match.length || 0};
    }));
  });

  return q.all(parsingAllFiles);
}).then(function(stats) {
  var normalized = stats.reduce(function(normalized, stat) {
    normalized[stat.count] = normalized[stat.count] || 0;
    normalized[stat.count]++;
    return normalized;
  }, {});

  console.log(normalized);
}).done();

output.txt

$ node count-exports.js
{ '0': 4,
  '1': 84,
  '2': 11,
  '3': 5,
  '4': 2,
  '5': 3,
  '7': 1,
  '8': 2,
  '9': 1,
  '10': 2,
  '14': 1,
  '33': 1,
  '67': 1,
  '93': 1,
  '94': 1,
  '97': 1,
  '108': 1 }