From 53e7181e009efcdcad182d485972bfbfda982fc0 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Fri, 29 Mar 2013 21:36:57 +0000
Subject: Allow HTML elements to be reused in HTML generation

---
 lib/html-generator.js         | 27 ++++++++++++++++++++++++---
 lib/styles.js                 | 23 ++++++++++++++++++++---
 tests/html-generator.tests.js | 17 +++++++++++++++--
 3 files changed, 59 insertions(+), 8 deletions(-)

diff --git a/lib/html-generator.js b/lib/html-generator.js
index 247ca09..5f2befa 100644
--- a/lib/html-generator.js
+++ b/lib/html-generator.js
@@ -1,5 +1,7 @@
 var util = require("util");
 
+var _ = require("underscore");
+
 exports.HtmlGenerator = HtmlGenerator;
 
 
@@ -17,10 +19,20 @@ function HtmlGenerator() {
     }
     
     function style(style) {
-        popAll();
-        style.forEach(function(tagName) {
-            push(tagName);
+        var firstFreshPartIndex = findIndex(style, function(part) {
+            return part.fresh;
         });
+        
+        var partIndex = 0;
+        while (partIndex < firstFreshPartIndex && style[partIndex].tagName === stack[partIndex]) {
+            partIndex++;
+        }
+        while (stack.length > partIndex) {
+            pop();
+        }
+        for (; partIndex < style.length; partIndex++) {
+            push(style[partIndex].tagName);
+        }
     }
     
     function push(element) {
@@ -54,3 +66,12 @@ function escapeHtml(value) {
         .replace(/</g, '&lt;')
         .replace(/>/g, '&gt;');
 }
+
+function findIndex(array, predicate) {
+    for (var i = 0; i < array.length; i++) {
+        if (predicate(array[i])) {
+            return i;
+        }
+    }
+    return -1;
+}
diff --git a/lib/styles.js b/lib/styles.js
index d3aa0a4..06d63a8 100644
--- a/lib/styles.js
+++ b/lib/styles.js
@@ -1,10 +1,27 @@
+var _ = require("underscore");
+
 exports.topLevelElement = topLevelElement;
 exports.elements = elements;
+exports.element = element;
 
 function topLevelElement(tagName) {
-    return elements([tagName]);
+    return elements([element(tagName, {fresh: true})]);
+}
+
+function elements(elementStyles) {
+    return elementStyles.map(function(elementStyle) {
+        if (_.isString(elementStyle)) {
+            return element(elementStyle);
+        } else {
+            return elementStyle;
+        }
+    });
 }
 
-function elements(tagNames) {
-    return tagNames;
+function element(tagName, options) {
+    options = options || {};
+    return {
+        tagName: tagName,
+        fresh: options.fresh
+    };
 }
diff --git a/tests/html-generator.tests.js b/tests/html-generator.tests.js
index 822aed9..a98ee70 100644
--- a/tests/html-generator.tests.js
+++ b/tests/html-generator.tests.js
@@ -14,13 +14,26 @@ describe('HtmlGenerator', function() {
     test('HTML-escapes text', function() {
         var generator = new HtmlGenerator();
         generator.text("<");
-        return assert.equal("&lt;", generator.asString());
+        return assert.equal(generator.asString(), "&lt;");
     });
     
     test('asString closes all elements', function() {
         var generator = new HtmlGenerator();
         generator.style(styles.elements(["p", "span"]));
         generator.text("Hello!");
-        return assert.equal("<p><span>Hello!</span></p>", generator.asString());
+        return assert.equal(generator.asString(), "<p><span>Hello!</span></p>");
+    });
+    
+    test('can leave some HTML elements for next style', function() {
+        var generator = new HtmlGenerator();
+        var listStyle = styles.elements([
+            styles.element("ul", {fresh: false}),
+            styles.element("li", {fresh: true})
+        ])
+        generator.style(listStyle);
+        generator.text("Apple");
+        generator.style(listStyle);
+        generator.text("Banana");
+        return assert.equal(generator.asString(), "<ul><li>Apple</li><li>Banana</li></ul>");
     });
 })
-- 
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