Add ability to change field content before sending form tracking (close snowplow#465)

Author: mhadam

src/js/forms.js

@@ -58,6 +58,9 @@ object.getFormTrackingManager = function (core, trackerId, contextAdder) {
 	// Filter to determine which form fields should be tracked
 	var fieldFilter = function () { return true };
 
+	// Default function applied to all elements, optionally overridden by transform field
+	var fieldTransform = function (x) { return x };
+
 	/*
 	 * Get an identifier for a form, input, textarea, or select element
 	 */
@@ -123,7 +126,7 @@ object.getFormTrackingManager = function (core, trackerId, contextAdder) {
 		return function (e) {
 			var elt = e.target;
 			var type = (elt.nodeName && elt.nodeName.toUpperCase() === 'INPUT') ? elt.type : null;
-			var value = (elt.type === 'checkbox' && !elt.checked) ? null : elt.value;
+			var value = (elt.type === 'checkbox' && !elt.checked) ? null : fieldTransform(elt.value);
 			core.trackFormChange(getParentFormName(elt), getFormElementName(elt), elt.nodeName, type, helpers.getCssClasses(elt), value, contextAdder(context));
 		};
 	}
@@ -135,6 +138,9 @@ object.getFormTrackingManager = function (core, trackerId, contextAdder) {
 		return function (e) {
 			var elt = e.target;
 			var innerElements = getInnerFormElements(elt);
+			lodash.forEach(innerElements, function (innerElement) {
+				innerElement.value = fieldTransform(innerElement.value);
+			});
 			core.trackFormSubmission(getFormElementName(elt), helpers.getCssClasses(elt), innerElements, contextAdder(context));
 		};
 	}
@@ -148,6 +154,7 @@ object.getFormTrackingManager = function (core, trackerId, contextAdder) {
 			if (config) {
 				formFilter = helpers.getFilter(config.forms, true);
 				fieldFilter = helpers.getFilter(config.fields, false);
+				fieldTransform = helpers.getTransform(config.fields);
 			}
 		},
 

src/js/lib/helpers.js

@@ -186,7 +186,7 @@
 	 *
 	 * @param object criterion Either {whitelist: [array of allowable strings]}
 	 *                             or {blacklist: [array of allowable strings]}
-	 *                             or {filter: function (elt) {return whether to track the element}}
+	 *                             or {filter: function (elt) {return whether to track the element}
 	 * @param boolean byClass Whether to whitelist/blacklist based on an element's classes (for forms)
 	 *                        or name attribute (for fields)
 	 */
@@ -226,6 +226,25 @@
 		}
 	};
 
+	/**
+	 * Convert a criterion object to a transform function
+	 *
+	 * @param object criterion {transform: function (elt) {return the result of transform function applied to element}
+	 */
+	object.getTransform = function (criterion) {
+		if (!lodash.isObject(criterion)) {
+			return function(x) { return x };
+		}
+
+		if (criterion.hasOwnProperty('transform')) {
+			return criterion.transform;
+		} else {
+			return function(x) { return x };
+		}
+
+        return function(x) { return x };
+	};
+
 	/**
 	 * Add a name-value pair to the querystring of a URL
 	 *

tests/pages/integration-template.html

@@ -83,7 +83,7 @@
 
 		// track unhandled exception
 		window.snowplow("enableErrorTracking");
-		function raiseException() { notExiststentObject.notExistentProperty(); }
+		function raiseException() { notExistentObject.notExistentProperty(); }
 		setTimeout(raiseException, 2500);
 
 	</script>