Merge pull request #60 from stoeffel/compose-pass-all-args

pass all arguments to the first function

compose.js

@@ -12,7 +12,9 @@
 module.exports = compose;
 
 function compose(f,g) {
-  return function composed(x) { 
-    return f(g(x));
+  return function composed(/* args */) { 
+    var args = Array.prototype.slice.call(arguments);
+
+    return f(g.apply(null, args));
   } 
 }

test/test-compose.js

@@ -17,6 +17,19 @@ describe('compose', function() {
     done();
   });
 
+  it('compose(f, sum)(x, y) should be identical to f(sum(x, y))', function(done) {
+    var f = function(x) { return x * x; }
+    var sum = function(x, y) { return x + y; }
+    var x = Math.random();
+    var y = Math.random();
+    var expected = f(sum(x, y));
+    var composed = compose(f, sum);
+    var actual = composed(x, y);
+    expect(actual).to.eql(expected);
+    done();
+  });
+
+
   it('compose(f, g)(x) should be identical to [x].map(g).map(f)[0]', function(done) {
     var f = function(x) { return -x; }
     var g = function(x) { return x * 5; }