map-values.js

var Promise = require('bluebird');
    _ = require('lodash');

/**
 * Map an object, or a promise of an object, with the given `mapper` function
 * with the signature `(value, key, obj)` where `value` is an object's `key`
 * property's value.
 *
 * If the `mapper` function returns promises or thenables, the returned promise
 * will wait for all the mapped results to be resolved as well.
 *
 * @param {Object|Promise e Object} obj
 * @param {Function}                fn
 * @returns {Promise e Object} mapped_obj
 */

function mapValuesP(obj, fn) {
  return Promise.cast(obj).then(function(obj) {
    var keys = Object.keys(obj);
    var valuesP = Promise.map(keys, function(key) {
      return fn(obj[key], key, obj);
    });

    return valuesP.then(_.partial(_.zipObject, keys));
  });
}
exports.mapValuesP = mapValuesP;

should have support for a context object
(this is not the most efficient approach - it's more of a spec, than anything else)