mungedb-aggregate/lib/pipeline/accumulators/AddToSetAccumulator.js

"use strict";

/** 
 * Create an expression that finds the sum of n operands.
 * @class AddSoSetAccumulator
 * @namespace mungedb-aggregate.pipeline.accumulators
 * @module mungedb-aggregate
 * @constructor
**/
var AddToSetAccumulator = module.exports = function AddToSetAccumulator(/* ctx */){
	if (arguments.length !== 0) throw new Error("zero args expected");
	this.set = {};
	//this.itr = undefined; /* Shoudln't need an iterator for the set */
	//this.ctx = undefined; /* Not using the context object currently as it is related to sharding */
	base.call(this);
}, klass = AddToSetAccumulator, Accumulator = require("./Accumulator"), base = Accumulator, proto = klass.prototype = Object.create(base.prototype, {constructor:{value:klass}});

// PROTOTYPE MEMBERS
proto.getOpName = function getOpName(){
	return "$addToSet";
};

proto.getFactory = function getFactory(){
	return klass;	// using the ctor rather than a separate .create() method
};

proto.evaluate = function evaluate(doc) {
	if (arguments.length !== 1) throw new Error("One and only one arg expected");
	var rhs = this.operands[0].evaluate(doc);
	if (rhs === undefined) return;
	this.set[JSON.stringify(rhs)] = rhs;
};

proto.getValue = function getValue() {
	var setValues = [];
	for (var setKey in this.set) {
		setValues.push(this.set[setKey]);
	}
	return setValues;
};