docs: function resolveArray(arg) {
    var resolvedArray = new Array(arg.length);
    return arg
        .reduce(function(soFar, value, index) {
          return soFar
              .then(resolveItem.bind(null, value))
              .then(function(value) {
                resolvedArray[index] = value;
              });
        }, Promise.resolve())
        .then(function() {
          return resolvedArray;
        });
  }