added ability to call methods by name in the chain, fixes #7

README.md

@@ -35,7 +35,7 @@ var line = d3.svg.line()
 ```
 
 This is very common D3 callback code. Here is the same code with callbacks refactored
-to use *d3-helpers*
+with *d3-helpers*
 
 ```js
 var line = d3.svg.line()
@@ -63,20 +63,21 @@ augmented by other tiny functions. First the *d3h* function itself
 
 Returns a function that can chain property access and function composition.
 
-`d3h('propertyName', fnToApply, 'anotherPropertyName', orAnotherFn, ...);`
+`d3h('propertyName', fnToApply, 'method name to call', 'anotherPropertyName', orAnotherFn, ...);`
 
 ```js
 var foo = {
+  getName: function() { return this.name; },
   name: 'foo'
 };
 function concatSelf(x) { return x + x; }
 function add2(x) { return x + 2; }
-var f = d3h('name', concatSelf, 'length', add2);
+var f = d3h('getName', concatSelf, 'length', add2);
 f(foo) // returns 8
 
 // f is the same as
 function (obj) {
-  return add2(concatSelf(obj.name).length);
+  return add2(concatSelf(obj.getName()).length);
 }
 ```
 
@@ -88,6 +89,9 @@ Use on `d` argument:
   .(d3h.d('length', xScale));
 ```
 
+When calling a method on the object, `this` is bound to the
+object, and it is passed itself as first argument.
+
 ### d3h.i
 
 Same chaining as `d3h.d` but operates on the second argument, usually the index

bower.json

@@ -1,7 +1,7 @@
 {
   "name": "d3-helpers",
   "main": "index.js",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "homepage": "https://github.com/bahmutov/d3-helpers",
   "license": "MIT",
   "ignore": [

index.js

@@ -9,7 +9,11 @@
         return function (d) {
           fns.forEach(function (fn) {
             if (typeof fn === 'string') {
-              d = d[fn];
+              if (typeof d[fn] === 'function') {
+                d = d[fn].call(d, d);
+              } else {
+                d = d[fn];
+              }
             } else if (typeof fn === 'function') {
               d = fn(d);
             } else {

package.json

@@ -1,7 +1,7 @@
 {
   "name": "d3-helpers",
   "description": "Little utility D3 functions",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "author": "Gleb Bahmutov <gleb.bahmutov@gmail.com>",
   "bugs": {
     "url": "https://github.com/bahmutov/d3-helpers/issues"

test/helpers.spec.js

@@ -35,6 +35,25 @@ describe('d3h d3-helpers', function () {
       }
       expect(explicit(foo)).to.equal(8);
     });
+
+    it('can call functions', function () {
+      var data = {
+        name: function () {
+          return 'foo';
+        }
+      };
+      expect(d3h('name')(data)).to.equal('foo');
+    });
+
+    it('method, get property, execute function', function () {
+      var data = {
+        self: function () {
+          return this;
+        },
+        age: 10
+      };
+      expect(d3h('self', 'age', add2)(data)).to.equal(12);
+    });
   });
 
   it('is a collection of functions', function () {