Add support for function-bind operator e.g. func::bind(this)

azu · May 23, 2016 · e641c27 · e641c27
1 parent bb7c982
commit e641c27
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diff --git 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
@@ -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));
+        });
     });
 });