.babelrc

{
  "presets": [
    "es2015"
  ],
  "plugins": [
    "transform-runtime"
  ],
}

index.es6

var React = require('react');
var ReactDOMServer = require('react-dom/server');
var iterable = new Map();

iterable.set('a', React.createElement('div', null, 1));
iterable.set('b', React.createElement('div', null, 2));

console.log(ReactDOMServer.renderToStaticMarkup(React.createElement('div', null, iterable)));

index.js

'use strict';

var _map = require('babel-runtime/core-js/map');

var _map2 = _interopRequireDefault(_map);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

var React = require('react');
var ReactDOMServer = require('react-dom/server');
var iterable = new _map2.default();

iterable.set('a', React.createElement('div', null, 1));
iterable.set('b', React.createElement('div', null, 2));

console.log(ReactDOMServer.renderToStaticMarkup(React.createElement('div', null, iterable)));

output-nodev0.10.txt

/project/node_modules/fbjs/lib/invariant.js:46
    throw error;
          ^
Invariant Violation: Objects are not valid as a React child (found: object with keys {_i, _f, _l, _s}). If you meant to render a collection of children, use an array instead or wrap the object using createFragment(object) from the React add-ons.

output-nodev5.txt

Warning: Using Maps as children is not yet fully supported. It is an experimental feature that might be removed. Convert it to a sequence / iterable of keyed ReactElements instead.
<div><div>1</div><div>2</div></div>