docs: function singlyMixin(dest, src, merge, inclProto) {
          for (var prop in src) {
              if (inclProto || src.hasOwnProperty(prop)) {
                  var val = src[prop];
  
                  if (merge &&
                          typeof dest[prop] !== 'undefined' &&
                          typeof val === 'object' &&
                          val !== null &&
                          !Array.isArray(val)) {
  
                      if (typeof dest[prop] !== 'object') {
                          dest[prop] = {};
                      }
  
                      singlyMixin(dest[prop], val, merge, inclProto);
  
                  } else {
                      try {
                          dest[prop] = val;
                      } catch (_) {
                      }
                  }
              }
          }
      }