From fc3d6a0f8faf979bd6903a8167c56d25cdf319fc Mon Sep 17 00:00:00 2001
From: mohammad ali seif kashani <seifkashani14@gmail.com>
Date: Fri, 18 Dec 2020 21:46:16 +0330
Subject: [PATCH 1/3] transition function implemented #2850

---
 modules/_transition.js | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 modules/_transition.js

diff --git a/modules/_transition.js b/modules/_transition.js
new file mode 100644
index 000000000..f9c8fa30f
--- /dev/null
+++ b/modules/_transition.js
@@ -0,0 +1,33 @@
+export function getTogglingfunction() {
+    if (arguments.length == 0) {
+        function inner(input) {
+            return !input;
+        }
+        return inner;
+    } else if (arguments.length != 1) {
+        var args = arguments;
+        function inner(input){
+            let all_arguments = Array.from(args);
+            all_arguments_length = all_arguments.length;
+            index = all_arguments.indexOf(input);
+            return all_arguments[(index + 1) % all_arguments_length];
+        }
+        return inner
+    } else if (arguments[0] instanceof Array){
+        args = arguments[0];
+        function inner(input){
+            let all_arguments = args;
+            all_arguments_length = all_arguments.length;
+            index = all_arguments.indexOf(input);
+            return all_arguments[(index + 1) % all_arguments_length];
+        }
+        return inner   
+    } else {
+        obj = arguments[0];
+        function inner(input) {
+            inner_obj = obj;
+            return inner_obj[input];
+        }
+        return inner
+    }
+}
\ No newline at end of file

From c3967228dbedea322688e0f7ec7f4eb22083d69a Mon Sep 17 00:00:00 2001
From: mohammad ali seif kashani <seifkashani14@gmail.com>
Date: Sun, 20 Dec 2020 23:58:20 +0330
Subject: [PATCH 2/3] findKeys implemented

---
 modules/_findkeys.js | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 modules/_findkeys.js

diff --git a/modules/_findkeys.js b/modules/_findkeys.js
new file mode 100644
index 000000000..b4221707f
--- /dev/null
+++ b/modules/_findkeys.js
@@ -0,0 +1,16 @@
+import cb from './_cb.js';
+import keys from './keys.js';
+
+ 
+function findKeys(obj, predicate, context) {
+  predicate = cb(predicate, context);
+  var _keys = keys(obj), key;
+  var arr = [];
+  for (var i = 0, length = _keys.length; i < length; i++) {
+    key = _keys[i];
+    if (predicate(obj[key], key, obj)) {
+        arr.push(key);
+    }
+  }
+  return arr;
+}
\ No newline at end of file

From 9f03948bfacc3610c7f0c9f16e0ac55d4fd54e08 Mon Sep 17 00:00:00 2001
From: mohammad ali seif kashani <seifkashani14@gmail.com>
Date: Fri, 8 Jan 2021 14:44:11 +0330
Subject: [PATCH 3/3] transition function added to index.js + test implemented
 for this function

---
 modules/index.js                          |  1 +
 modules/{_transition.js => transition.js} |  2 +-
 test/utility.js                           | 21 +++++++++++++++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)
 rename modules/{_transition.js => transition.js} (95%)

diff --git a/modules/index.js b/modules/index.js
index c48ca7e9e..1b9d0a37b 100644
--- a/modules/index.js
+++ b/modules/index.js
@@ -87,6 +87,7 @@ export { default as result } from './result.js';
 export { default as uniqueId } from './uniqueId.js';
 export { default as chain } from './chain.js';
 export { default as iteratee } from './iteratee.js';
+export { default as transition} from './transition'
 
 // Function (ahem) Functions
 // -------------------------
diff --git a/modules/_transition.js b/modules/transition.js
similarity index 95%
rename from modules/_transition.js
rename to modules/transition.js
index f9c8fa30f..2792b1226 100644
--- a/modules/_transition.js
+++ b/modules/transition.js
@@ -1,4 +1,4 @@
-export function getTogglingfunction() {
+export default function getTogglingfunction() {
     if (arguments.length == 0) {
         function inner(input) {
             return !input;
diff --git a/test/utility.js b/test/utility.js
index b0cd4941c..97179e1c9 100644
--- a/test/utility.js
+++ b/test/utility.js
@@ -465,4 +465,25 @@
     assert.strictEqual(template(), '<<\nx\n>>');
   });
 
+  
+  QUnit.test('transition function - toggles the input in several values.', function(assert) {
+    // assert.expect(1);
+    // var template = _.template('<<\nx\n>>', null, {evaluate: /<<(.*?)>>/g});
+    // assert.strictEqual(template(), '<<\nx\n>>');
+    toggler = _.getTogglingfunction()
+    var input = true;
+    assert.strictEqual(toggler(input), false)
+    toggler = _.getTogglingfunction([1, 2, 3])
+    var input = 3;
+    assert.strictEqual(toggler(input), 1)
+    toggler = _.getTogglingfunction({
+      'red': 'green',
+      'yellow': 'red',
+      'green': 'yellow'
+    })
+    var input = 'green';
+    assert.strictEqual(toggler(input), 'yellow')   
+  });
+
 }());
+