autoform-arrays.js

// Track arrays; this allows us to add/remove fields or groups of fields for an array
// but still easily respect minCount and maxCount, and properly add/remove the same
// items from the database once the form is submitted.

ArrayTracker = function afArrayTracker() {
  var self = this;
  self.info = {};
};

ArrayTracker.prototype.getMinMax = function atGetMinMax(ss, field, overrideMinCount, overrideMaxCount) {
  var defs = AutoForm.Utility.getDefs(ss, field);

  // minCount is set by the schema, but can be set higher on the field attribute
  overrideMinCount = overrideMinCount || 0;
  var minCount = defs.minCount || 0;
  minCount = Math.max(overrideMinCount, minCount);

  // maxCount is set by the schema, but can be set lower on the field attribute
  overrideMaxCount = overrideMaxCount || Infinity;
  var maxCount = defs.maxCount || Infinity;
  maxCount = Math.min(overrideMaxCount, maxCount);

  return {minCount: minCount, maxCount: maxCount};
};

ArrayTracker.prototype.initForm = function atInitForm(formId) {
	var self = this;

	if (self.info[formId])
		return;

	self.info[formId] = {};
};

ArrayTracker.prototype.getForm = function atInitForm(formId) {
	var self = this;
	self.initForm(formId);
	return self.info[formId];
};

ArrayTracker.prototype.ensureField = function atEnsureField(formId, field) {
	var self = this;
	self.initForm(formId);

	if (!self.info[formId][field]) {
		self.resetField(formId, field);
	}
};

ArrayTracker.prototype.initField = function atInitField(formId, field, ss, docCount, overrideMinCount, overrideMaxCount) {
	var self = this;
	self.ensureField(formId, field);

	if (self.info[formId][field].array != null)
		return;

	// If we have a doc: The count should be the maximum of docCount or schema minCount or field minCount or 1.
	// If we don't have a doc: The count should be the maximum of schema minCount or field minCount or 1.
	var range = self.getMinMax(ss, field, overrideMinCount, overrideMaxCount);
	var arrayCount = Math.max(range.minCount, (docCount == null) ? 1 : docCount);

	// If this is an array of objects, collect names of object props
	var childKeys = [];
	if (ss.schema(field + '.$').type === Object) {
    childKeys = ss.objectKeys(SimpleSchema._makeGeneric(field) + '.$');
	}

	var loopArray = [];
	for (var i = 0; i < arrayCount; i++) {
		var loopCtx = createLoopCtx(formId, field, i, childKeys, overrideMinCount, overrideMaxCount);
		loopArray.push(loopCtx);
	};

	self.info[formId][field].array = loopArray;
	var count = loopArray.length;
	self.info[formId][field].count = count;
	self.info[formId][field].visibleCount = count;
	self.info[formId][field].deps.changed();
};

ArrayTracker.prototype.resetField = function atResetField(formId, field) {
	var self = this;
	self.initForm(formId);

	if (!self.info[formId][field]) {
		self.info[formId][field] = {
			deps: new Tracker.Dependency()
		};
	}

	self.info[formId][field].array = null;
	self.info[formId][field].count = 0;
	self.info[formId][field].visibleCount = 0;
	self.info[formId][field].deps.changed();
};

ArrayTracker.prototype.resetForm = function atResetForm(formId) {
	var self = this;
	_.each(self.info[formId], function (info, field) {
		self.resetField(formId, field);
	});
};

ArrayTracker.prototype.untrackForm = function atUntrackForm(formId) {
	var self = this;
	self.info[formId] = {};
};

ArrayTracker.prototype.tracksField = function atTracksField(formId, field) {
	var self = this;
	self.ensureField(formId, field);
	self.info[formId][field].deps.depend();
	return !!self.info[formId][field].array;
};

ArrayTracker.prototype.getField = function atGetField(formId, field) {
	var self = this;
	self.ensureField(formId, field);
	self.info[formId][field].deps.depend();
	return self.info[formId][field].array;
};

ArrayTracker.prototype.getCount = function atGetCount(formId, field) {
	var self = this;
	self.ensureField(formId, field);
	self.info[formId][field].deps.depend();
	return self.info[formId][field].count;
};

ArrayTracker.prototype.getVisibleCount = function atGetVisibleCount(formId, field) {
	var self = this;
	self.ensureField(formId, field);
	self.info[formId][field].deps.depend();
	return self.info[formId][field].visibleCount;
};

ArrayTracker.prototype.isFirstFieldlVisible = function atIsFirstFieldlVisible(formId, field, currentIndex) {
	var self = this;
	self.ensureField(formId, field);
	self.info[formId][field].deps.depend();
	var firstVisibleField = _.find(self.info[formId][field].array, function(currentField) {
		return !currentField.removed;
	});
	return (firstVisibleField && firstVisibleField.index === currentIndex);
};

ArrayTracker.prototype.isLastFieldlVisible = function atIsLastFieldlVisible(formId, field, currentIndex) {
	var self = this;
	self.ensureField(formId, field);
	self.info[formId][field].deps.depend();
	var lastVisibleField = _.last(_.filter(self.info[formId][field].array, function(currentField) {
		return !currentField.removed;
	}));
	return (lastVisibleField && lastVisibleField.index === currentIndex);
};

ArrayTracker.prototype.addOneToField = function atAddOneToField(formId, field, ss, overrideMinCount, overrideMaxCount) {
  var self = this;
  self.ensureField(formId, field);

  if (!self.info[formId][field].array) {
  	return;
  }

  var currentCount = self.info[formId][field].visibleCount
  var maxCount = self.getMinMax(ss, field, overrideMinCount, overrideMaxCount).maxCount;

  if (currentCount < maxCount) {
	  var i = self.info[formId][field].array.length;

	  // If this is an array of objects, collect names of object props
	  var childKeys = [];
	  if (ss.schema(field + '.$').type === Object) {
      childKeys = ss.objectKeys(SimpleSchema._makeGeneric(field) + '.$');
	  }

	  var loopCtx = createLoopCtx(formId, field, i, childKeys, overrideMinCount, overrideMaxCount);

	  self.info[formId][field].array.push(loopCtx);
	  self.info[formId][field].count++;
	  self.info[formId][field].visibleCount++;
	  self.info[formId][field].deps.changed();
  }
};

ArrayTracker.prototype.removeFromFieldAtIndex = function atRemoveFromFieldAtIndex(formId, field, index, ss, overrideMinCount, overrideMaxCount) {
  var self = this;
  self.ensureField(formId, field);

  if (!self.info[formId][field].array) {
  	return;
  }

  var currentCount = self.info[formId][field].visibleCount;
  var minCount = self.getMinMax(ss, field, overrideMinCount, overrideMaxCount).minCount;

  if (currentCount > minCount) {
    self.info[formId][field].array[index].removed = true;
    self.info[formId][field].count--;
    self.info[formId][field].visibleCount--;
    self.info[formId][field].deps.changed();
  }
}

/*
 * PRIVATE
 */
var createLoopCtx = function(formId, field, index, childKeys, overrideMinCount, overrideMaxCount) {
  var loopCtx = {
  	formId:         formId,
  	arrayFieldName: field, 
  	name:           field + '.' + index,
  	index:          index, 
  	minCount:       overrideMinCount,
  	maxCount:       overrideMaxCount
  };

  // If this is an array of objects, add child key names under loopCtx.current[childName] = fullKeyName
  if (childKeys.length) {
    loopCtx.current = {};
	_.each(childKeys, function (k) {
	  loopCtx.current[k] = field + '.' + index + '.' + k;
    });
  }

  return loopCtx;
}