Allow promise resolution in Dust global helpers

linkedin · Mar 26, 2015 · ebb9985 · ebb9985
1 parent 519526f
commit ebb9985
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Showing 3 changed files with 38 additions and 32 deletions.
diff --git a/lib/dust.js b/lib/dust.js
@@ -803,11 +803,16 @@
   };
 
   Chunk.prototype.helper = function(name, context, bodies, params) {
-    var chunk = this;
+    var chunk = this,
+        ret;
     // handle invalid helpers, similar to invalid filters
     if(dust.helpers[name]) {
       try {
-        return dust.helpers[name](chunk, context, bodies, params);
+        ret = dust.helpers[name](chunk, context, bodies, params);
+        if (dust.isThenable(ret)) {
+          return this.await(ret, context, bodies);
+        }
+        return ret;
       } catch(err) {
         dust.log('Error in helper `' + name + '`: ' + err.message, ERROR);
         return chunk.setError(err);

diff --git a/test/jasmine-test/spec/coreTests.js b/test/jasmine-test/spec/coreTests.js
@@ -832,11 +832,26 @@ var coreTests = [
 	  },
 	  {
 		name:     "thenable deep section, traverse outside",
-		source:   "Eventually my {#magic.ally}{prince} {delicious}{/magic.ally} will come",
-		context:  { "prince": "Prince", "magic": new FalsePromise(null, {"ally": {"delicious": new FalsePromise(null, "Lucky Charms")} }) },
+		source:   "Eventually my {#magic.ally}{prince} {delicious} {charms}{/magic.ally} will come",
+		base:     { charms: new FalsePromise(null, "Charms") },
+		context:  { "prince": "Prince", "magic": new FalsePromise(null, {"ally": {"delicious": new FalsePromise(null, "Lucky")} }) },
 		expected: "Eventually my Prince Lucky Charms will come",
 		message: "should reserve an async section for a deep-reference thenable and not blow the stack"
 	  },
+	  {
+		name:     "thenable resolved by global helper",
+		source:   '{@promise resolve="helper"}I am a big {.}!{/promise}',
+		context:  {},
+		expected: "I am a big helper!",
+		message:  "Dust helpers that return thenables are resolved in context"
+	  },
+	  {
+		name:     "thenable rejected by global helper",
+		source:   '{@promise reject="error"}I am a big helper!{:error}I am a big {.}!{/promise}',
+		context:  {},
+		expected: "I am a big error!",
+		message:  "Dust helpers that return thenables are rejected in context"
+	  },
 	  {
 		name:     "thenable error",
 		source:   "{promise}",
@@ -1329,8 +1344,8 @@ var coreTests = [
                    '{>"{parentTemplate}"/} | additional parent output'].join("\n"),
         context:  { "loadTemplate": function(chunk, context, bodies, params)
                     {
-                      var source = dust.testHelpers.tap(params.source, chunk, context),
-                          name = dust.testHelpers.tap(params.name, chunk, context);
+                      var source = context.resolve(params.source),
+                          name = context.resolve(params.name);
                       dust.loadSource(dust.compile(source, name));
                       return chunk.write('');
                     },

diff --git a/test/jasmine-test/spec/testHelpers.js b/test/jasmine-test/spec/testHelpers.js
@@ -1,35 +1,21 @@
 (function (root, factory) {
   if (typeof exports === 'object') {
-    factory(require('../../../lib/dust'));
+    factory(require('../../../lib/dust'), require('ayepromise'));
   } else {
-    factory(root.dust);
+    factory(root.dust, ayepromise);
   }
-}(this, function(dust) {
-  dust.testHelpers = {};
-  dust.testHelpers.tap = function(input, chunk, context) {
-    // return given input if there is no dust reference to resolve
-    var output = input;
-    // dust compiles a string/reference such as {foo} to function,
-    if (typeof input === 'function') {
-      // just a plain function (a.k.a anonymous functions) in the context, not a dust `body` function created by the dust compiler
-      if (input.isFunction === true) {
-        output = input();
-      } else {
-        output = '';
-        chunk.tap(function(data){
-           output += data;
-           return '';
-          }).render(input, context).untap();
-        if (output === '') {
-          output = false;
-        }
-      }
-    }
-   return output;
-  };
-
+}(this, function(dust, ayepromise) {
   dust.helpers = {};
   dust.helpers.error = function(chunk, context, bodies, params) {
     throw params.errorMessage;
   };
+  dust.helpers.promise = function(chunk, context, bodies, params) {
+    var defer = ayepromise.defer();
+    if (params.reject) {
+      defer.reject(params.reject);
+    } else {
+      defer.resolve(params.resolve);
+    }
+    return defer.promise;
+  };
 }));