Implement updateIn method

index.js

@@ -400,6 +400,20 @@ DotObject.prototype.set = function (path, val, obj, merge) {
   return obj
 }
 
+/**
+ *
+ * Use given function to update a property on an object using dot notation.
+ *
+ * @param {String} path
+ * @param {Function} fn
+ * @param {Object} obj
+ */
+DotObject.prototype.updateIn = function (path, fn, obj) {
+  var originalValue = this.pick(path, obj)
+  this.set(path, fn(originalValue), obj)
+  return obj
+}
+
 /**
  *
  * Transform an object
@@ -479,6 +493,7 @@ DotObject.copy = wrap('copy')
 DotObject.object = wrap('object')
 DotObject.str = wrap('str')
 DotObject.set = wrap('set')
+DotObject.updateIn = wrap('updateIn')
 DotObject.del = DotObject.remove = wrap('remove')
 DotObject.dot = wrap('dot')
 

test/update-in.js

@@ -0,0 +1,18 @@
+'use strict'
+
+require('should')
+var Dot = require('../index')
+
+describe('updateIn:', function () {
+  it('Should be able to update value at given path using given function', function () {
+    var obj = {
+      counter: 1
+    }
+
+    Dot.updateIn('counter', function (currentValue) {
+      return currentValue + 1;
+    }, obj)
+
+    obj.should.eql({counter: 2})
+  })
+})