mungedb-aggregate/lib/pipeline/expressions/SetUnionExpression.js

"use strict";

/**
 * A $setunion pipeline expression.
 * @see evaluateInternal
 * @class SetUnionExpression
 * @namespace mungedb-aggregate.pipeline.expressions
 * @module mungedb-aggregate
 * @constructor
 **/
var SetUnionExpression = module.exports = function SetUnionExpression() {
		this.fixedArity(2);
		if (arguments.length !== 2) throw new Error("two args expected");
		base.call(this);
}, klass = SetUnionExpression,
		base = require("./NaryExpression"),
		proto = klass.prototype = Object.create(base.prototype, {
				constructor: {
						value: klass
				}
		});

// DEPENDENCIES
var Value = require("../Value"),
		Expression = require("./Expression");

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

/**
 * Takes 2 objects. Unions the objects
 * @method evaluateInternal
 **/
proto.evaluateInternal = function evaluateInternal(doc) {
		var object1 = this.operands[0].evaluateInternal(doc),
				object2 = this.operands[1].evaluateInternal(doc);
		if (object1 instanceof Array) throw new Error(this.getOpName() + ": object 1 must be an object");
		if (object2 instanceof Array) throw new Error(this.getOpName() + ": object 2 must be an object");

		var object3 = {};
		for (var attrname1 in object1) {
				object3[attrname1] = object1[attrname1];
		}
		for (var attrname2 in object2) {
				object3[attrname2] = object2[attrname2];
		}

		return object3;
};

/** Register Expression */
Expression.registerExpression("$setunion", SetUnionExpression.parse);