Implements the #has Block helper

closes #2115
- Added new #has block helper
- Added several tests for #has helper

core/server/helpers/index.js

@@ -572,6 +572,37 @@ coreHelpers.foreach = function (context, options) {
     return ret;
 };
 
+// ### Has Helper
+// `{{#has tag="video, music"}}`
+// Checks whether a post has at least one of the tags
+coreHelpers.has = function (options) {
+    var tags = _.pluck(this.tags, 'name'),
+        tagList = options && options.hash ? options.hash.tag : false;
+
+    function evaluateTagList(expr, tags) {
+        return expr.split(',').map(function (v) {
+            return v.trim();
+        }).reduce(function (p, c) {
+            return p || (_.findIndex(tags, function (item) {
+                // Escape regex special characters
+                item = item.replace(/[\-\/\\\^$*+?.()|\[\]{}]/g, '\\$&');
+                item = new RegExp(item, 'i');
+                return item.test(c);
+            }) !== -1);
+        }, false);
+    }
+
+    if (!tagList) {
+        errors.logWarn("Invalid or no attribute given to has helper");
+        return;
+    }
+
+    if (tagList && evaluateTagList(tagList, tags)) {
+        return options.fn(this);
+    }
+    return options.inverse(this);
+};
+
 // ### Pagination Helper
 // `{{pagination}}`
 // Outputs previous and next buttons, along with info about the current page
@@ -702,6 +733,8 @@ registerHelpers = function (adminHbs, assetHash) {
 
     registerThemeHelper('foreach', coreHelpers.foreach);
 
+    registerThemeHelper('has', coreHelpers.has);
+
     registerThemeHelper('page_url', coreHelpers.page_url);
 
     registerThemeHelper('pageUrl', coreHelpers.pageUrl);

core/test/unit/server_helpers_index_spec.js

@@ -427,6 +427,64 @@ describe('Core Helpers', function () {
         });
     });
 
+    describe('has Block Helper', function () {
+        it('has loaded has block helper', function () {
+            should.exist(handlebars.helpers.has);
+        });
+
+        it('should handle tag list that validates true', function () {
+            var fn = sinon.spy(),
+                inverse = sinon.spy();
+
+            helpers.has.call(
+                {tags: [{ name: 'foo'}, { name: 'bar'}, { name: 'baz'}]},
+                {hash: { tag: 'invalid, bar, wat'}, fn: fn, inverse: inverse}
+            );
+
+            fn.called.should.be.true;
+            inverse.called.should.be.false;
+        });
+
+        it('should handle tags with case-insensitivity', function () {
+            var fn = sinon.spy(),
+                inverse = sinon.spy();
+
+            helpers.has.call(
+                {tags: [{ name: 'ghost'}]},
+                {hash: { tag: 'GhoSt'}, fn: fn, inverse: inverse}
+            );
+
+            fn.called.should.be.true;
+            inverse.called.should.be.false;
+        });
+
+        it('should handle tag list that validates false', function () {
+            var fn = sinon.spy(),
+                inverse = sinon.spy();
+
+            helpers.has.call(
+                {tags: [{ name: 'foo'}, { name: 'bar'}, { name: 'baz'}]},
+                {hash: { tag: 'much, such, wow'}, fn: fn, inverse: inverse}
+            );
+
+            fn.called.should.be.false;
+            inverse.called.should.be.true;
+        });
+
+        it('should not do anything when an invalid attribute is given', function () {
+            var fn = sinon.spy(),
+                inverse = sinon.spy();
+
+            helpers.has.call(
+                {tags: [{ name: 'foo'}, { name: 'bar'}, { name: 'baz'}]},
+                {hash: { invalid: 'nonsense'}, fn: fn, inverse: inverse}
+            );
+
+            fn.called.should.be.false;
+            inverse.called.should.be.false;
+        });
+    });
+
     describe('url Helper', function () {
         it('has loaded url helper', function () {
             should.exist(handlebars.helpers.url);