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

"use strict";

/** 
 * A $strcasecmp pipeline expression.
 * @see evaluate
 * @class StrcasecmpExpression
 * @namespace mungedb-aggregate.pipeline.expressions
 * @module mungedb-aggregate
 * @constructor
 **/
var StrcasecmpExpression = module.exports = function StrcasecmpExpression() {
		this.fixedArity(2);
		if (arguments.length !== 0) throw new Error("zero args expected");
		base.call(this);
}, klass = StrcasecmpExpression,
		base = require("./NaryExpression"),
		proto = klass.prototype = Object.create(base.prototype, {
				constructor: {
						value: klass
				}
		});

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

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

/** 
 * Takes in two strings. Returns a number. $strcasecmp is positive if the first string is “greater than” the second and negative if the first string is “less than” the second. $strcasecmp returns 0 if the strings are identical.
 * @method evaluate
 **/
proto.evaluateInternal = function evaluateInternal(doc) {
		this.checkArgCount(2);
		var val1 = this.operands[0].evaluateInternal(doc),
				val2 = this.operands[1].evaluateInternal(doc),
				str1 = Value.coerceToString(val1).toUpperCase(),
				str2 = Value.coerceToString(val2).toUpperCase(),
				cmp = Value.compare(str1, str2);
		return cmp;
};

/** Register Expression */
Expression.registerExpression("$strcasecmp", StrcasecmpExpression.parse);