added new jQuery plugin called attrFilter along with unit tests for it

2 files changed, 54 insertions, 4 deletions

diff --git a/src/js/fiveui/injected/jquery-plugins.js b/src/js/fiveui/injected/jquery-plugins.js
index 5a32031..1589972 100644
--- a/src/js/fiveui/injected/jquery-plugins.js
+++ b/src/js/fiveui/injected/jquery-plugins.js
@@ -43,7 +43,8 @@ fiveui.jquery.hasText = function (text) {
 };
 
 /**
- * Filter for elements which lack of the given attribute.
+ * Filter for elements which lack of the given attribute. (see also
+ * fiveui.jquery.attrFilter)
  *
  * Example:
  *
@@ -133,6 +134,24 @@ fiveui.jquery.cssIsNot = function (prop, set, fn) {
 }
 
 /**
+ * General attribute filter
+ *
+ * @description This plugin filters for elements whose attribute `a` pass
+ * the predicate `fn`, which should take a string and return true or false.
+ * Elements that don't have the attribute are automatically filtered out.
+ *
+ * @param {String} a element attribute name
+ * @param {Function} fn a predicate to run on the element attribute
+ * @returns {Object} jQuery object
+ */
+fiveui.jquery.attrFilter = function (a, fn) {
+  return this.filter(function () {
+    var x = $(this).attr(a);
+    return x != undefined && fn(x);
+  });
+}
+
+/**
  * Filter out elements that do not contain the attribute
  * href=`href`.
  *
diff --git a/src/js/tests/specs/jquery-plugins.js b/src/js/tests/specs/jquery-plugins.js
index 7fc196b..04eb0fb 100644
--- a/src/js/tests/specs/jquery-plugins.js
+++ b/src/js/tests/specs/jquery-plugins.js
@@ -86,7 +86,9 @@ describe('jQuery plugins', function () {
     });
 
     it('filters out everything', function () {
-      expect($t.notColorSet(['#ffffff', '#000000', '#e1e1e1']).length).toEqual(0);
+      expect(
+        $t.notColorSet(['#ffffff', '#000000', '#e1e1e1']).length).toEqual(0
+      );
     });
   });
 
@@ -99,11 +101,15 @@ describe('jQuery plugins', function () {
     var $t = $(htm);
 
     it('filters out colors', function () {
-      expect($t.cssIsNot('color', ['#ffffff', '#000000'], fiveui.color.colorToHexWithDefault).length).toEqual(1);
+      expect($t.cssIsNot('color',
+                         ['#ffffff', '#000000'],
+                         fiveui.color.colorToHexWithDefault).length).toEqual(1);
     });
 
     it('filters out background-colors', function () {
-      expect($t.cssIsNot('background-color', ['#141414', '#232323'], fiveui.color.colorToHexWithDefault).length).toEqual(3);
+      expect($t.cssIsNot('background-color',
+                         ['#141414', '#232323'],
+                         fiveui.color.colorToHexWithDefault).length).toEqual(3);
     });
 
     it('filters out elements of different type', function () {
@@ -111,6 +117,31 @@ describe('jQuery plugins', function () {
     });
   });
 
+  describe('fiveui.jquery.attrFilter', function () {
+    var isEmpty = function (s) { return $.trim(s) == ""; };
+
+    it('filters for zero elements with empty alt', function () {
+      var $elt = $('<a href="foo" alt="bar"><a href="beel" alt="bar">');
+      expect($elt.attrFilter('alt', isEmpty).length).toEqual(0);
+    });
+
+    it('filters for one element with empty alt', function () {
+      var $elt = $('<a href="foo" alt=""><a href="beel" alt="bar">');
+      expect($elt.attrFilter('alt', isEmpty).length).toEqual(1);
+    });
+
+    it('filters out elements that don\'t have the attribute', function () {
+      var $elt = $('<a href="foo"><a href="beel">');
+      expect($elt.attrFilter('alt', isEmpty).length).toEqual(0);
+    });
+
+    it('filters for elements with alt containing foo', function () {
+      var hasFoo = function (s) { return /foo/.test(s); };
+      var $elt = $('<a href="foo" alt="barfoo"><a href="beel" alt="bar">');
+      expect($elt.attrFilter('alt', hasFoo).length).toEqual(1);
+    });
+  });
+
   describe('fiveui.jquery.linksTo', function () {
     it('filters out elements with no href', function () {
       expect($('<p>foo</p>').linksTo('bar').length).toEqual(0);