Merge pull request #150 from jtwebman/fix-nested-async-helpers

Got nested async helpers working

lib/generate-id.js

@@ -0,0 +1,16 @@
+'use strict';
+
+var alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_';
+
+function generateId(length) {
+  if (!length) {
+    length = 8;
+  }
+  var res = '';
+  for (var i = 0; i < length; ++i) {
+    res += alphabet[Math.floor(Math.random() * alphabet.length)];
+  }
+  return res;
+}
+
+module.exports = generateId;

lib/hbs.js

@@ -4,7 +4,8 @@ var fs = require('fs');
 var path = require('path');
 var readdirp = require('readdirp');
 var handlebars = require('handlebars');
-var async = require('./async');
+var resolver = require('./resolver');
+var _ = require('lodash');
 
 /**
  * Regex pattern for layout directive. {{!< layout }}
@@ -357,15 +358,28 @@ ExpressHbs.prototype.compile = function(source, filename) {
  */
 ExpressHbs.prototype.registerAsyncHelper = function(name, fn) {
   this.handlebars.registerHelper(name, function(context, options) {
+    var resolverCache = this.resolverCache ||
+      _.get(context, 'data.root.resolverCache') ||
+      _.get(options, 'data.root.resolverCache');
+    if (!resolverCache) {
+      throw new Error('Could not find resolver cache in async helper ' + name + '.');
+    }
     if (options && fn.length > 2) {
-      var resolver = function(arr, cb) {
+      var resolveFunc = function(arr, cb) {
         return fn.call(this, arr[0], arr[1], cb);
       };
 
-      return async.resolve(resolver.bind(this), [context, options]);
+      return resolver.resolve(
+        resolverCache,
+        resolveFunc.bind(this),
+        [context, options]
+      );
     }
-
-    return async.resolve(fn.bind(this), context);
+    return resolver.resolve(
+      resolverCache,
+      fn.bind(this),
+      context
+    );
   });
 };
 
@@ -419,6 +433,7 @@ ExpressHbs.prototype.___express = function ___express(filename, source, options,
   }
 
   options.blockCache = {};
+  options.resolverCache = {};
 
   this.viewsDir = options.settings.views || this.viewsDirOpt;
   var self = this;
@@ -581,18 +596,32 @@ ExpressHbs.prototype.___express = function ___express(filename, source, options,
     });
   }
 
-  // Handles waiting for async helpers
-  function handleAsync(err, res) {
-    if (err) return cb(err);
-    async.done(function(values) {
+  function replaceValue(values, text) {
+    if (typeof text === 'string') {
       Object.keys(values).forEach(function(id) {
-        res = res.replace(id, function() {
+        text = text.replace(id, function() {
           return values[id];
         });
-        res = res.replace(self.Utils.escapeExpression(id), function() {
+        text = text.replace(self.Utils.escapeExpression(id), function() {
           return self.Utils.escapeExpression(values[id]);
         });
       });
+    }
+    return text;
+  }
+
+  // Handles waiting for async helpers
+  function handleAsync(err, res) {
+    if (err) return cb(err);
+    resolver.done(options.resolverCache, function(err, values) {
+      if (err) return cb(err);
+      Object.keys(values).forEach(function(key) {
+        values[key] = replaceValue(values, values[key]);
+      });
+      res = replaceValue(values, res);
+      if (resolver.hasResolvers(res)) {
+        return handleAsync(null, res);
+      }
       cb(null, res);
     });
   }

lib/resolver.js

@@ -0,0 +1,45 @@
+'use strict';
+
+var Promise = require('bluebird');
+
+var generateId = require('./generate-id');
+
+var ID_LENGTH = 8;
+var MS_CHECK_TIME = 10;
+var ID_PREFIX = '__aSyNcId_<_';
+var ID_SUFFIX = '__';
+
+function resolve(cache, fn, context) {
+  var id = ID_PREFIX + generateId(ID_LENGTH) + ID_SUFFIX;
+  cache[id] = new Promise(function(passed, failed) {
+    try {
+      fn(context, function(res) {
+        passed(res);
+      });
+    } catch(error) {
+      failed(error);
+    }
+  });
+  return id;
+}
+
+function done(cache, callback) {
+  Promise.props(cache).then(function(values) {
+    callback(null, values);
+  }).catch(function(error) {
+    callback(error);
+  });
+}
+
+function hasResolvers(text) {
+  if (text.search(ID_PREFIX) > 0) {
+    return true;
+  }
+  return false;
+}
+
+module.exports = {
+  done: done,
+  hasResolvers: hasResolvers,
+  resolve: resolve
+};

package.json

@@ -37,8 +37,10 @@
     "supertest": "2.0.1"
   },
   "dependencies": {
+    "bluebird": "^3.5.1",
     "handlebars": "4.0.11",
     "js-beautify": "1.7.5",
+    "lodash": "^4.17.10",
     "readdirp": "2.1.0"
   }
 }

test/apps/async/index.js

@@ -6,6 +6,54 @@ var fs = require('fs');
 var path = require('path');
 var url = require('url');
 
+var pages = [
+  {
+    id: 1,
+    title: 'Title 1'
+  },
+  {
+    id: 2,
+    title: 'Title 2'
+  },
+  {
+    id: 3,
+    title: 'Title 3'
+  }
+]
+
+var comments = [
+  {
+    id: 1,
+    page: 1,
+    subject: 'Title 1 Comment 1',
+    auther: 'JT'
+  },
+  {
+    id: 2,
+    page: 1,
+    subject: 'Title 1 Comment 2',
+    auther: 'Anna'
+  },
+  {
+    id: 3,
+    page: 1,
+    subject: 'Title 1 Comment 3',
+    auther: 'Jane'
+  },
+  {
+    id: 4,
+    page: 1,
+    subject: 'Title 1 Comment 4',
+    auther: 'Bob'
+  },
+  {
+    id: 5,
+    page: 4,
+    subject: 'This should not show!',
+    auther: 'Jill'
+  }
+]
+
 function getRandomNumber(min, max) {
   return Math.random() * (max - min) + min;
 }
@@ -31,12 +79,47 @@ function create(hbs, env) {
     });
   });
 
+  app.get('/fail', function (req, res) {
+    res.render('failer');
+  });
+
   hbs.registerAsyncHelper('user', function(username, resultcb) {
     setTimeout(function() {
       resultcb(username);
     }, getRandomNumber(100, 900))
   });
 
+  hbs.registerAsyncHelper('pages', function(options, resultcb) {
+    var self = this;
+    setTimeout(function() {
+      var result = [];
+      for(var i = 0; i < pages.length; i++) {
+        options.data.page = pages[i];
+        result.push(options.fn.call(self, pages[i], options));
+      }
+      resultcb(result.join(''));
+    }, getRandomNumber(100, 900))
+  });
+
+  hbs.registerAsyncHelper('comments', function(options, resultcb) {
+    var self = this;
+    setTimeout(function() {
+      var result = [];
+      for(var i = 0; i < comments.length; i++) {
+        if (options.hash.page === comments[i].page) {
+          result.push(options.fn(comments[i]));
+        }
+      }
+      resultcb(result.join(''));
+    }, getRandomNumber(100, 300))
+  });
+
+  hbs.registerAsyncHelper('failer', function(_, resultcb) {
+    setTimeout(function() {
+      resultcb(options.fn());
+    }, 100);
+  })
+
   return app;
 }
 

test/apps/async/views/failer.hbs

@@ -0,0 +1,4 @@
+{{#contentFor "title"}}
+  Failer
+{{/contentFor}}
+<span id="text">This should fail {{#failer}}for sure{{/failer}}.</span>

test/apps/async/views/index.hbs

@@ -2,3 +2,15 @@
   {{message}} {{{user username}}}
 {{/contentFor}}
 <span id="text">This should welcome {{username}}.</span>
+<div class="pages">
+{{#pages filter="tags:test"}}
+  <div class="page">
+    <span class="title">{{title}}</title>
+    <div class="top-comments">
+    {{#comments top="3" page=id}}
+      <span class="subject">{{subject}}</span>-<span class="auther">{{auther}}</span>
+    {{/comments}}
+    </div>
+  </div>
+{{/pages}}
+</div>