From f183d2d79f7035d8e581cef32e4a2092c6c84f08 Mon Sep 17 00:00:00 2001
From: Stefan Penner <stefan.penner@gmail.com>
Date: Fri, 11 Sep 2015 18:12:58 -0700
Subject: [PATCH 1/3] WeakMap RFC

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 text/0066-template.md | 90 +++++++++++++++++++++++++++++++++++++++++++
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 create mode 100644 text/0066-template.md

diff --git a/text/0066-template.md b/text/0066-template.md
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+- Start Date: 2015-09-11
+- RFC PR: https://github.com/emberjs/ember.js/pull/12224
+- Ember Issue: (leave this empty)
+
+# Summary
+
+Introduce `Ember.WeakMap` (`@ember/weakmap`), an ES6 enspired WeakMap. A
+WeakMap provides a mechanism for storing and retriving private state. The
+WeakMap itself does not retain a reference to the state, allowing the state to
+be reclaimed when the key is reclaimed.
+
+A traditional WeakMap (and the one that will be part of the language) allows
+for weakness from key -> map, and also from map -> key. This allows either the
+Map, or the key being reclaimed to also release the state.
+
+Unforunately, this bi-directional weakness is problemative to polyfil. Luckily,
+uni-directional weakness, in either direction, "just works". A polyfil must
+just choose a direction.
+
+*Note: Just like ES2015 WeakMap, only non null Objects can be used as keys*
+*Note: `Ember.WeakMap` can be used interchangibly with the ES2015 WeakMap. This
+will allow us to eventually cut over entirely to the Native WeakMap.*
+ 
+# Motivation
+
+It is a common pattern to want to store private state about a specific object.
+When one stores this private state off-object, it can be tricky to understand
+when to release the state. When one stores this state on-object, it will be
+released when the object is released. Unfortunately, storing the state
+on-object without poluting the object itself is non-obvious.
+
+As it turns out, Ember's Meta already solves this problem for
+listeners/caches/chains/descriptors etc. Unfortunately today, there is no
+public API for apps or addons to utilize this. `Ember.WeakMap` aims to be
+exactly that API.
+
+# Detailed design
+
+## Public API
+
+```js
+import WeakMap from '@ember/weak-map'
+
+var private = new WeakMap();
+var object = {};
+var otherObject = {};
+
+private.set(object, {
+  id: 1,
+  name: 'My File',
+  progress: 0
+}) === private;
+
+private.get(object) === {
+  id: 1,
+  name: 'My File',
+  progress: 0
+});
+
+
+private.has(object) === true;
+private.has(otherObject) === false;
+
+private.delete(object) === private;
+private.has(object) === false;
+```
+
+## Implementation Details
+
+The backing store for `Ember.WeakMap` will reside in a lazy `ownMap` named
+`weak` on the key objects `__meta__` object.
+
+Each `WeakMap` has its own internal GUID, which will be the name of its slot,
+in the key objects meta weak bucket. This will allow one object to belong in
+multiple weakMaps without chance of collision.
+
+Concrete Implementation: https://github.com/emberjs/ember.js/pull/12224
+
+# Drawbacks
+
+* implementing bi-direction Weakness in userland is problematic.
+* Using WeakMap will insert a non-enumerable `meta` onto the key Object.
+
+# Alternatives
+
+* Weakness could be implemented in the other direction, but this has questionable utility.
+
+# Unresolved questions
+
+N/A

From 89f08b9dcdda132b75eab878687cc312e502562c Mon Sep 17 00:00:00 2001
From: Stefan Penner <stefan.penner@gmail.com>
Date: Sat, 12 Sep 2015 14:26:32 -0700
Subject: [PATCH 2/3] Update 0066-template.md

---
 text/0066-template.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/text/0066-template.md b/text/0066-template.md
index 3ef031f87d..e8e6a8728c 100644
--- a/text/0066-template.md
+++ b/text/0066-template.md
@@ -34,6 +34,11 @@ listeners/caches/chains/descriptors etc. Unfortunately today, there is no
 public API for apps or addons to utilize this. `Ember.WeakMap` aims to be
 exactly that API.
 
+Some examples:
+
+* https://github.com/offirgolan/ember-cp-validations/blob/master/addon/utils/cycle-breaker.js
+* https://github.com/stefanpenner/ember-state-services/ (will soon utilize the user-land polyfil of this) to prevent common leaks.
+
 # Detailed design
 
 ## Public API

From ddf743b73cb9f046c84268c3f840133b48799eac Mon Sep 17 00:00:00 2001
From: Stefan Penner <stefan.penner@gmail.com>
Date: Thu, 24 Sep 2015 10:53:04 -0700
Subject: [PATCH 3/3] Update 0066-template.md

---
 text/0066-template.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/text/0066-template.md b/text/0066-template.md
index e8e6a8728c..f71171d650 100644
--- a/text/0066-template.md
+++ b/text/0066-template.md
@@ -80,6 +80,7 @@ in the key objects meta weak bucket. This will allow one object to belong in
 multiple weakMaps without chance of collision.
 
 Concrete Implementation: https://github.com/emberjs/ember.js/pull/12224
+Polyfill: https://www.npmjs.com/package/ember-weakmap
 
 # Drawbacks