Added excerpt helper

closes #471

- strips HTML aggressively
- with unit tests

core/server/helpers/index.js

@@ -57,6 +57,38 @@ coreHelpers = function (ghost) {
     });
 
 
+    // ### Excerpt Helper
+    //
+    // *Usage example:*
+    // `{{excerpt}}`
+    // `{{excerpt words=50}}`
+    // `{{excerpt characters=256}}`
+    //
+    // Attempts to remove all HTML from the string, and then shortens the result according to the provided option.
+    //
+    // Defaults to words=50
+    //
+    // **returns** SafeString truncated, HTML-free content.
+    //
+    ghost.registerThemeHelper('excerpt', function (options) {
+        var truncateOptions = (options || {}).hash || {},
+            excerpt;
+
+        truncateOptions = _.pick(truncateOptions, ["words", "characters"]);
+
+        /*jslint regexp:true */
+        excerpt = String(this.content).replace(/<\/?[^>]+>/gi, "");
+        /*jslint regexp:false */
+
+        if (!truncateOptions.words && !truncateOptions.characters) {
+            truncateOptions.words = 50;
+        }
+
+        return new hbs.handlebars.SafeString(
+            downsize(excerpt, truncateOptions)
+        );
+    });
+
     /**
      * [ description]
      *

core/test/unit/frontend_helpers_index_spec.js

@@ -61,6 +61,65 @@ describe('Core Helpers', function () {
         });
     });
 
+    describe('Excerpt Helper', function () {
+
+        it('has loaded excerpt helper', function () {
+            should.exist(handlebars.helpers.excerpt);
+        });
+
+        it('can render excerpt', function () {
+            var content = "Hello World",
+                rendered = handlebars.helpers.excerpt.call({content: content});
+
+            should.exist(rendered);
+            rendered.string.should.equal(content);
+        });
+
+        it('does not output HTML', function () {
+            var content = '<p>There are <br />10<br> types<br/> of people in <img src="a">the world:'
+                        + '<img src=b alt=\"c\"> those who <img src="@" onclick="javascript:alert(\'hello\');">'
+                        + "understand trinary</p>, those who don't <div style='' class=~/'-,._?!|#>and"
+                        + "< test > those<<< test >>> who mistake it &lt;for&gt; binary.",
+                expected = "There are 10 types of people in the world: those who understand trinary, those who don't "
+                         + "and those>> who mistake it &lt;for&gt; binary.",
+                rendered = handlebars.helpers.excerpt.call({content: content});
+
+            should.exist(rendered);
+            rendered.string.should.equal(expected);
+
+        });
+
+        it('can truncate content by word', function () {
+            var content = "<p>Hello <strong>World! It's me!</strong></p>",
+                expected = "Hello World",
+                rendered = (
+                    handlebars.helpers.excerpt.call(
+                        {content: content},
+                        {"hash": {"words": 2}}
+                    )
+                );
+
+            should.exist(rendered);
+            rendered.string.should.equal(expected);
+        });
+
+        it('can truncate content by character', function () {
+            var content = "<p>Hello <strong>World! It's me!</strong></p>",
+                expected = "Hello Wo",
+                rendered = (
+                    handlebars.helpers.excerpt.call(
+                        {content: content},
+                        {"hash": {"characters": 8}}
+                    )
+                );
+
+            should.exist(rendered);
+            rendered.string.should.equal(expected);
+        });
+
+
+    });
+
     describe('Navigation Helper', function () {
 
         it('has loaded nav helper', function () {