code: function formatCount(n, opts) {
      n = n || 0;
      opts = opts || {};
  
      var i = 0,
          base = opts.base || 1000,
          sep = opts.sep || '',
          maxLen = opts.maxLen || 3,
          precision = maxLen - 1;
  
      for (; n > base; i += 1) {
          n /= base;
      }
  
      if (!i) {
          precision = 0;
      } else if (n > 100) {
          precision -= 2;
      } else if (n > 10) {
          precision -= 1;
      }
  
      return n.toFixed(Math.max(0, precision)) + sep +
          ['', 'k', 'M', 'G', 'T'][Math.min(i, 4)];
  }
docs: Like formatSize, but more generic. Returns a human-readable format
  of an integer using metric prefixes. The caller is expected to append any
  unit string if necessary.
  
  @param {integer} n The number to format.
  @param {Object} [opts={}] Formatting options. These include:
  - {integer} [maxLen] Max number of digits in the output.
  - {integer} [base=1000] Base for the prefixes (usually 1000 or 1024).
  - {string} [sep=''] Separator between numeric value and metric prefix.