First commit! Forward port of the Underscore engine.

Author: geoffp

lib/engine_underscore.js

@@ -0,0 +1,141 @@
+/*
+ * underscore pattern engine for patternlab-node - v0.15.1 - 2015
+ *
+ * Geoffrey Pursell, Brian Muenzenmeyer, and the web community.
+ * Licensed under the MIT license.
+ *
+ * Many thanks to Brad Frost and Dave Olsen for inspiration, encouragement, and advice.
+ *
+ */
+
+
+/*
+ * ENGINE SUPPORT LEVEL:
+ *
+ * Basic. We can't call partials from inside underscore templates yet, but we
+ * can render templates with backing JSON.
+ *
+ */
+
+
+"use strict";
+
+var _ = require('underscore');
+var partialRegistry = {};
+
+// extend underscore with partial-ing methods and other necessary tooling
+// HANDLESCORE! UNDERBARS!
+function addParentContext(data, currentContext) {
+  return Object.assign({}, currentContext, data);
+}
+
+_.mixin({
+  renderAtomicPartial: function (partialKey, data, currentContext) {
+    return _.renderPartial(partialRegistry[partialKey], data, currentContext);
+  },
+  renderPartial: function (partial, dataIn, currentContext) {
+    var data = dataIn || {};
+    var compiled;
+    if (dataIn && currentContext &&
+        dataIn instanceof Object && currentContext instanceof Object) {
+      data = addParentContext(data, currentContext);
+    }
+
+    compiled = _.template(partial);
+
+    return compiled(data);
+  },
+  assignContext: function (viewModel, data) {
+    return viewModel(data);
+  },
+
+  /* eslint-disable no-eval, no-unused-vars */
+  getPath: function (pathString, currentContext, debug) {
+    try {
+      var result = eval('currentContext.' + pathString);
+      if (debug) {
+        console.log("getPath result = ", result);
+      }
+      return result;
+    } catch (e) {
+      return null;
+    }
+  }
+});
+
+var engine_underscore = {
+  engine: _,
+  engineName: 'underscore',
+  engineFileExtension: '.html',
+
+  // partial expansion is only necessary for Mustache templates that have
+  // style modifiers or pattern parameters (I think)
+  expandPartials: false,
+
+  // regexes, stored here so they're only compiled once
+  findPartialsRE: /<%=[ \t]*_\.renderPartial[ \t]*\((?:"([^"].*?)"|'([^'].*?)')/g, // TODO,
+  findPartialsWithStyleModifiersRE: /<%= _.renderPartial\((.*?)\).*?%>/g, // TODO
+  findPartialsWithPatternParametersRE: /<%= _.renderPartial\((.*?)\).*?%>/g, // TODO
+  findListItemsRE: /({{#( )?)(list(I|i)tems.)(one|two|three|four|five|six|seven|eight|nine|ten|eleven|twelve|thirteen|fourteen|fifteen|sixteen|seventeen|eighteen|nineteen|twenty)( )?}}/g,
+
+  // render it
+  renderPattern: function renderPattern(pattern, data, partials) {
+    var renderedHTML;
+    var compiled;
+
+    try {
+      compiled = _.template(pattern.extendedTemplate);
+    } catch (e) {
+      console.log(`Error compiling template ${pattern.patternName}:`, pattern.extendedTemplate);
+    }
+
+    // This try-catch is necessary because references to undefined variables
+    // in underscore templates are eval()ed directly as javascript, and as
+    // such will throw very real exceptions that will shatter the whole build
+    // process if we don't handle them.
+    try {
+      renderedHTML = compiled(_.extend(data || {}, {
+        _allData: data,
+        _partials: partials
+      }));
+    } catch (e) {
+      var errorMessage = `Error in underscore template ${pattern.patternName} (${pattern.relPath}): [${e.toString()}]`;
+      console.log(errorMessage);
+      renderedHTML = `<h1>Error in underscore template ${pattern.patternName} (${pattern.relPath})</h1><p>${e.toString()}</p>`;
+    }
+
+    return renderedHTML;
+  },
+
+  registerPartial: function (oPattern) {
+    partialRegistry[oPattern.key] = oPattern.template;
+  },
+
+  // find and return any {{> template-name }} within pattern
+  findPartials: function findPartials(pattern) {
+    var matches = pattern.template.match(this.findPartialsRE);
+    return matches;
+  },
+  findPartialsWithStyleModifiers: function () {
+    return [];
+  },
+
+  // returns any patterns that match {{> value(foo:"bar") }} or {{>
+  // value:mod(foo:"bar") }} within the pattern
+  findPartialsWithPatternParameters: function () {
+    return [];
+  },
+  findListItems: function (pattern) {
+    var matches = pattern.template.match(this.findListItemsRE);
+    return matches;
+  },
+
+  // given a pattern, and a partial string, tease out the "pattern key" and
+  // return it.
+  findPartial: function (partialString) {
+    var partial = partialString.replace(this.findPartialsRE, '$1');
+    return partial;
+  }
+};
+
+module.exports = engine_underscore;

package.json

@@ -1,10 +1,10 @@
 {
-  "name": "patternengine-node-handlebars",
-  "description": "The Handlebars engine for Pattern Lab / Node",
+  "name": "patternengine-node-underscore",
+  "description": "The Underscore engine for Pattern Lab / Node",
   "version": "1.0.0",
-  "main": "lib/engine_handlebars.js",
+  "main": "lib/engine_underscore.js",
   "dependencies": {
-    "handlebars": "^4.0.5"
+    "underscore": "^1.8.3"
   },
   "devDependencies": {},
   "keywords": [
@@ -14,11 +14,11 @@
     "Grunt",
     "Gulp",
     "Javascript",
-    "Handlebars"
+    "Underscore"
   ],
   "repository": {
     "type": "git",
-    "url": "https://github.com/pattern-lab/patternengine-node-handlebars.git"
+    "url": "https://github.com/pattern-lab/patternengine-node-underscore.git"
   },
   "bugs": "https://github.com/pattern-lab/patternlab-node/issues",
   "author": "Brian Muenzenmeyer & Geoffrey Pursell",