Support custom functions without signatures

sass · Feb 2, 2015 · d6ce2d4 · d6ce2d4
1 parent f152b8c
commit d6ce2d4
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Showing 2 changed files with 85 additions and 9 deletions.
diff --git a/lib/index.js b/lib/index.js
@@ -207,6 +207,45 @@ function tryCallback(callback, args) {
   }
 }
 
+/**
+ * Normalizes the signature of custom functions to make it possible to just supply the
+ * function name and have the signature default to `fn(...)`. The callback is adjusted
+ * to transform the input sass list into discrete arguments.
+ *
+ * @param {String} signature
+ * @param {Function} callback
+ * @return {Object}
+ * @api private
+ */
+
+function normalizeFunctionSignature(signature, callback) {
+  if (!/^\*|@warn|@error|@debug|\w+\(.*\)$/.test(signature)) {
+    if (!/\w+/.test(signature)) {
+      throw new Error('Invalid function signature format "' + signature + '"');
+    }
+
+    return {
+      signature: signature + '(...)',
+      callback: function() {
+        var args = Array.prototype.slice.call(arguments),
+            list = args.shift(),
+            i;
+
+        for (i = list.getLength() - 1; i >= 0; i--) {
+          args.unshift(list.getValue(i));
+        }
+
+        return callback.apply(this, args);
+      }
+    };
+  }
+
+  return {
+    signature: signature, 
+    callback: callback
+  };
+}
+
 /**
  * Require binding
  */
@@ -242,19 +281,23 @@ module.exports.render = function(options) {
     };
   }
 
-  if (options.functions) {
-    Object.keys(options.functions).forEach(function(signature) {
-      var callback = options.functions[signature];
+  var functions = options.functions;
+
+  if (functions) {
+    options.functions = {};
 
-      options.functions[signature] = function() {
+    Object.keys(functions).forEach(function(signature) {
+      var cb = normalizeFunctionSignature(signature, functions[signature]);
+
+      options.functions[cb.signature] = function() {
         var args = Array.prototype.slice.call(arguments),
             bridge = args.pop();
 
         function done(data) {
           bridge.success(data);
         }
 
-        var result = tryCallback(callback, args.concat(done));
+        var result = tryCallback(cb.callback, args.concat(done));
 
         if (result) {
           done(result);
@@ -277,12 +320,16 @@ module.exports.render = function(options) {
 module.exports.renderSync = function(options) {
   options = getOptions(options);
 
+  var functions = options.functions;
+
   if (options.functions) {
-    Object.keys(options.functions).forEach(function(signature) {
-      var callback = options.functions[signature];
+    options.functions = {};
+
+    Object.keys(functions).forEach(function(signature) {
+      var cb = normalizeFunctionSignature(signature, functions[signature]);
 
-      options.functions[signature] = function() {
-        return tryCallback(callback, arguments);
+      options.functions[cb.signature] = function() {
+        return tryCallback(cb.callback, arguments);
       };
     });
   }

diff --git a/test/api.js b/test/api.js
@@ -575,6 +575,21 @@ describe('api', function() {
       });
     });
 
+    it('should let us register custom functions without signatures', function(done) {
+      sass.render({
+        data: 'div { color: foo(20, 22); }',
+        success: function(result) {
+          assert.equal(result.css.trim(), 'div {\n  color: 42em; }');
+          done();
+        },
+        functions: {
+          foo: function(a, b) {
+            return new sass.types.Number(a.getValue() + b.getValue(), 'em');
+          }
+        }
+      });
+    });
+
     it('should fail when returning anything other than a sass value from a custom function', function(done) {
       sass.render({
         data: 'div { color: foo(); }',
@@ -706,6 +721,20 @@ describe('api', function() {
       done();
     });
 
+    it('should let us register custom functions without signatures', function(done) {
+      var result = sass.renderSync({
+        data: 'div { color: foo(20, 22); }',
+        functions: {
+          foo: function(a, b) {
+            return new sass.types.Number(a.getValue() + b.getValue(), 'em');
+          }
+        }
+      });
+
+      assert.equal(result.css.trim(), 'div {\n  color: 42em; }');
+      done();
+    });
+
     it('should fail when returning anything other than a sass value from a custom function', function(done) {
       assert.throws(function() {
         sass.renderSync({