Provide static method to check for valid operators

src/ol/expression/expression.js

@@ -136,6 +136,22 @@ ol.expression.Comparison = function(operator, left, right) {
 goog.inherits(ol.expression.Comparison, ol.expression.Expression);
 
 
+/**
+ * Determine if a given string is a valid comparison operator.
+ * @param {string} candidate Operator to test.
+ * @return {boolean} The operator is valid.
+ */
+ol.expression.Comparison.isValidOp = (function() {
+  var valid = {};
+  for (var key in ol.expression.ComparisonOp) {
+    valid[ol.expression.ComparisonOp[key]] = true;
+  }
+  return function isValidOp(candidate) {
+    return !!valid[candidate];
+  };
+}());
+
+
 /**
  * @inheritDoc
  */
@@ -276,6 +292,22 @@ ol.expression.Logical = function(operator, left, right) {
 goog.inherits(ol.expression.Logical, ol.expression.Expression);
 
 
+/**
+ * Determine if a given string is a valid logical operator.
+ * @param {string} candidate Operator to test.
+ * @return {boolean} The operator is valid.
+ */
+ol.expression.Logical.isValidOp = (function() {
+  var valid = {};
+  for (var key in ol.expression.LogicalOp) {
+    valid[ol.expression.LogicalOp[key]] = true;
+  }
+  return function isValidOp(candidate) {
+    return !!valid[candidate];
+  };
+}());
+
+
 /**
  * @inheritDoc
  */
@@ -341,6 +373,22 @@ ol.expression.Math = function(operator, left, right) {
 goog.inherits(ol.expression.Math, ol.expression.Expression);
 
 
+/**
+ * Determine if a given string is a valid math operator.
+ * @param {string} candidate Operator to test.
+ * @return {boolean} The operator is valid.
+ */
+ol.expression.Math.isValidOp = (function() {
+  var valid = {};
+  for (var key in ol.expression.MathOp) {
+    valid[ol.expression.MathOp[key]] = true;
+  }
+  return function isValidOp(candidate) {
+    return !!valid[candidate];
+  };
+}());
+
+
 /**
  * @inheritDoc
  */

src/ol/expression/parser.js

@@ -126,15 +126,15 @@ ol.expression.Parser.prototype.binaryPrecedence_ = function(token) {
 ol.expression.Parser.prototype.createBinaryExpression_ = function(operator,
     left, right) {
   var expr;
-  if (ol.expression.ComparisonOp.hasOwnProperty(operator)) {
+  if (ol.expression.Comparison.isValidOp(operator)) {
     expr = new ol.expression.Comparison(
         /** @type {ol.expression.ComparisonOp.<string>} */ (operator),
         left, right);
-  } else if (ol.expression.LogicalOp.hasOwnProperty(operator)) {
+  } else if (ol.expression.Logical.isValidOp(operator)) {
     expr = new ol.expression.Logical(
         /** @type {ol.expression.LogicalOp.<string>} */ (operator),
         left, right);
-  } else if (ol.expression.MathOp.hasOwnProperty(operator)) {
+  } else if (ol.expression.Math.isValidOp(operator)) {
     expr = new ol.expression.Math(
         /** @type {ol.expression.MathOp.<string>} */ (operator),
         left, right);