From e641c27759fa89a6430aaa92f85817f52b06557f Mon Sep 17 00:00:00 2001
From: Jay Phelps <hello@jayphelps.com>
Date: Sun, 22 May 2016 17:42:49 -0700
Subject: [PATCH] Add support for function-bind operator e.g. func::bind(this)

---
 src/idempotent-bind.js       | 10 ++++++++++
 test/idempotent-bind-test.js | 13 +++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/src/idempotent-bind.js b/src/idempotent-bind.js
index ac3b043..79c3261 100644
--- a/src/idempotent-bind.js
+++ b/src/idempotent-bind.js
@@ -43,6 +43,11 @@ function releaseBind(secondMap, thisArg) {
  * @template T
  */
 export function bind(target, thisArg) {
+    if (this !== undefined) {
+        target = this;
+        thisArg = target;
+    }
+
     var secondMap = map.get(target);
     // need to save the bound function into WeakMp.
     if (thisArg == null) {
@@ -65,6 +70,11 @@ export function bind(target, thisArg) {
  * @template T
  */
 export function unbind(target, thisArg) {
+    if (this !== undefined) {
+        target = this;
+        thisArg = target;
+    }
+
     if (typeof target !== "function") {
         throw new Error("target must be function.");
     }
diff --git a/test/idempotent-bind-test.js b/test/idempotent-bind-test.js
index 06be840..875023f 100644
--- a/test/idempotent-bind-test.js
+++ b/test/idempotent-bind-test.js
@@ -19,6 +19,12 @@ describe("idempotent-bind", function () {
             };
             assert(bind(f, null) === bind(f, null));
         });
+
+        it("supports implicit `target` from callee's `this`", function () {
+            var f = function () {
+            };
+            assert(bind.call(f, this) === bind.call(f, this));
+        });
     });
     describe("#unbind", function () {
         it("should release binding", function () {
@@ -41,5 +47,12 @@ describe("idempotent-bind", function () {
             var g = bind(f, null);
             assert(g === unbind(f, null));
         });
+        it("should release binding for implicit `target`", function () {
+            var f = function () {
+            };
+            var g = bind.call(f, this);
+            unbind.call(f, this);
+            assert(g !== bind.call(f, this));
+        });
     });
 });
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