From 8ac725b3420da6039b9063eb8a970c05a6833a85 Mon Sep 17 00:00:00 2001
From: Marian Schubert <marian.schubert@gmail.com>
Date: Thu, 18 Oct 2018 13:37:56 +0200
Subject: [PATCH] Implement updateIn method

---
 index.js          | 15 +++++++++++++++
 test/update-in.js | 18 ++++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 test/update-in.js

diff --git a/index.js b/index.js
index 7540e3f..cefb574 100644
--- a/index.js
+++ b/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')
 
diff --git a/test/update-in.js b/test/update-in.js
new file mode 100644
index 0000000..7627293
--- /dev/null
+++ b/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})
+  })
+})