Map and resolve all

map_and_resolve_all.js

var Q = require('q'),
    _ = require('lodash');

var mapAndResolveAll = _.compose(Q.all, _.map);

function loadWithPattern(pattern) {
  return function(entity) {
    return loadEntity(entity, pattern);
  };
}

function loadEntity(entity, pattern) {
  return entity.load(pattern);
}

var log = console.log.bind(console),

    // array of entities
    entities = [entity, entity, entity],

    // dummy load pattern
    pattern = {
      type: true
    };

mapAndResolveAll(entities, loadWithPattern(pattern)).then(log);
// wait 500 ms
// => [ { load: [Function], type: ... },
//      { load: [Function], type: ... },
//      { load: [Function], type: ... } ]


// equivalent to:
// var promises = _.map(entities, function(entity) {
//   return entity.load(pattern);
// });

// Q.all(promises).then(function(result) {
//   console.log(result);
// });