Add defaultsOn (#29)

* Add defaultsOn

* Get these trailing spaces out of Travis' face 👋

CHANGELOG.md

@@ -1,3 +1,6 @@
+# 1.7.0
+- Add `defaultsOn`
+
 # 1.6.0
 - Add `extendOn`
 

README.md

@@ -48,7 +48,7 @@ These methods provide alternative orderings that are sometimes more convenient.
 The idea of `In` methods is to name them by convention, so when ever you need a method that actually takes the collection first (e.g. a `get` where the data is static but the field is dynamic), you can just add `In` to the end (such as `getIn` which takes the object first)
 
 ### `On`s (Immutable False)
-`extendOn`
+`extendOn`, `defaultsOn`
 lodash/fp likes to keep things pure, but sometimes JS can get pretty dirty.
 These methods are alternatives for working with data that--for whatever the use case is--needs to be mutable
 Any methods that interact with mutable data will use the `On` convention (as it is some action occuring `On` some data)

package.json

@@ -1,6 +1,6 @@
 {
   "name": "futil-js",
-  "version": "1.6.0",
+  "version": "1.7.0",
   "description": "F(unctional) util(ities). Resistance is futile.",
   "main": "lib/futil-js.js",
   "scripts": {

src/conversion.js

@@ -9,6 +9,7 @@ export const includesIn = _.includes.convert({ rearg: false })
 // Mutables
 // ----------
 export const extendOn   = _.extend.convert({ immutable: false })
+export const defaultsOn = _.defaults.convert({ immutable: false })
 
 // This reduce based version is easier to maintain but requires calling `F.inversions.fn` instead of `F.fn`
 let inversionList = ['get', 'pick', 'includes'];

test/mutables.spec.js

@@ -6,18 +6,30 @@ const expect = chai.expect
 
 describe('Mutable FP Functions', function() {
     it('extendOn', function() {
-        let expected = f.extendOn({
+        expect(f.extendOn({
             a: 1
         }, {
             a: 2,
             b: 3,
             c: 4
+        })).to.deep.equal({
+            a: 2,
+            b: 3,
+            c: 4
         })
-
-        expect(expected).to.deep.equal({
+    })
+
+    it('defaultsOn', function() {
+        expect(f.defaultsOn({
             a: 2,
             b: 3,
             c: 4
+        }, {
+            a: 1
+        })).to.deep.equal({
+            a: 1,
+            b: 3,
+            c: 4
         })
     })
 })