Alternative implementations of some Ember.computed functions to avoid issues with broken ArrayComputed and ReduceComputed

unbork-arraycomputed-reducecomputed.js

Em.computed.map = function(key, callback) {
  return Em.computed(key + '.[]', function() {
    return Em.get(this, key).map(callback.bind(this));
  });
};

Em.computed.mapBy = function(key, property) {
  return Em.computed(key + '.@each.' + property, function() {
    return Em.get(this, key).mapBy(property);
  });
};

Em.computed.max = function(key) {
  return Em.computed(key + '.[]', function() {
    return max(Em.get(this, key));
  });
};

Em.computed.filterBy = function(key, property, value) {
  return Em.computed(key + '.@each.' + property, function() {
    return value === undefined ?
      Em.get(this, key).filterBy(property) :
      Em.get(this, key).filterBy(property, value);
  });
};

export function max(array, callback) {
  if (!callback) { callback = x => x; };
  if (typeof callback !== 'function') { throw new TypeError(); }

  var withNums = array.map(obj => ({
    obj: obj,
    num: callback(obj)
  }));

  var maxWithNum = withNums.reduce(
    (accum, item) => accum.num > item.num ? accum : item,
    { obj: null, num: Number.NEGATIVE_INFINITY });

  return maxWithNum.obj;
}

export default null;