Merge pull request #16215 from emberjs/move-each-proxy-to-meta

Move each proxy into a weak map

packages/ember-extension-support/lib/data_adapter.js

@@ -1,13 +1,12 @@
 import { getOwner } from 'ember-utils';
-import { get, run } from 'ember-metal';
+import { get, run, objectAt } from 'ember-metal';
 import {
   String as StringUtils,
   Namespace,
   Object as EmberObject,
   A as emberA,
   addArrayObserver,
-  removeArrayObserver,
-  objectAt
+  removeArrayObserver
 } from 'ember-runtime';
 
 /**

packages/ember-glimmer/lib/utils/iterable.ts

@@ -6,11 +6,16 @@ import {
   UpdatableTag,
 } from '@glimmer/reference';
 import { Opaque } from '@glimmer/util';
-import { get, isProxy, tagFor, tagForProperty } from 'ember-metal';
 import {
-  _contentFor,
-  isEmberArray,
+  get,
+  isProxy,
   objectAt,
+  tagFor,
+  tagForProperty
+} from 'ember-metal';
+import {
+  _contentFor,
+  isEmberArray
 } from 'ember-runtime';
 import { guidFor } from 'ember-utils';
 import { isEachIn } from '../helpers/each-in';

packages/ember-metal/lib/array.js

@@ -0,0 +1,7 @@
+export function objectAt(content, idx) {
+  if (typeof content.objectAt === 'function') {
+    return content.objectAt(idx);
+  } else {
+    return content[idx];
+  }
+}

packages/ember-metal/lib/chains.js

@@ -2,6 +2,7 @@ import { get } from './property_get';
 import { descriptorFor, meta as metaFor, peekMeta } from './meta';
 import { watchKey, unwatchKey } from './watch_key';
 import { cacheFor } from './computed';
+import { eachProxyFor } from './each_proxy';
 
 const FIRST_KEY = /^([^\.]+)/;
 
@@ -326,7 +327,9 @@ function lazyGet(obj, key) {
   }
 
   // Use `get` if the return value is an EachProxy or an uncacheable value.
-  if (isVolatile(obj, key, meta)) {
+  if (key === '@each') {
+    return eachProxyFor(obj);
+  } else if (isVolatile(obj, key, meta)) {
     return get(obj, key);
   // Otherwise attempt to get the cached value of the computed property
   } else {

packages/ember-metal/lib/each_proxy.js

@@ -0,0 +1,131 @@
+import { assert } from 'ember-debug';
+import { get } from './property_get';
+import { notifyPropertyChange } from './property_events';
+import { addObserver, removeObserver } from './observer';
+import { meta, peekMeta } from './meta';
+import { objectAt } from './array';
+
+const EACH_PROXIES = new WeakMap();
+
+export function eachProxyFor(array) {
+  let eachProxy = EACH_PROXIES.get(array);
+  if (eachProxy === undefined) {
+    eachProxy = new EachProxy(array);
+    EACH_PROXIES.set(array, eachProxy);
+  }
+  return eachProxy;
+}
+
+export function eachProxyArrayWillChange(array, idx, removedCnt, addedCnt) {
+  let eachProxy = EACH_PROXIES.get(array);
+  if (eachProxy !== undefined) {
+    eachProxy.arrayWillChange(array, idx, removedCnt, addedCnt);
+  }
+}
+
+export function eachProxyArrayDidChange(array, idx, removedCnt, addedCnt) {
+  let eachProxy = EACH_PROXIES.get(array);
+  if (eachProxy !== undefined) {
+    eachProxy.arrayDidChange(array, idx, removedCnt, addedCnt);
+  }
+}
+
+class EachProxy {
+  constructor(content) {
+    this._content = content;
+    this._keys = undefined;
+    meta(this);
+  }
+
+  // ..........................................................
+  // ARRAY CHANGES
+  // Invokes whenever the content array itself changes.
+
+  arrayWillChange(content, idx, removedCnt, addedCnt) {   // eslint-disable-line no-unused-vars
+    let keys = this._keys;
+    let lim = removedCnt > 0 ? idx + removedCnt : -1;
+    for (let key in keys) {
+      if (lim > 0) {
+        removeObserverForContentKey(content, key, this, idx, lim);
+      }
+    }
+  }
+
+  arrayDidChange(content, idx, removedCnt, addedCnt) {
+    let keys = this._keys;
+    let lim = addedCnt > 0 ? idx + addedCnt : -1;
+    let meta = peekMeta(this);
+    for (let key in keys) {
+      if (lim > 0) {
+        addObserverForContentKey(content, key, this, idx, lim);
+      }
+      notifyPropertyChange(this, key, meta);
+    }
+  }
+
+  // ..........................................................
+  // LISTEN FOR NEW OBSERVERS AND OTHER EVENT LISTENERS
+  // Start monitoring keys based on who is listening...
+
+  willWatchProperty(property) {
+    this.beginObservingContentKey(property);
+  }
+
+  didUnwatchProperty(property) {
+    this.stopObservingContentKey(property);
+  }
+
+  // ..........................................................
+  // CONTENT KEY OBSERVING
+  // Actual watch keys on the source content.
+
+  beginObservingContentKey(keyName) {
+    let keys = this._keys;
+    if (!keys) {
+      keys = this._keys = Object.create(null);
+    }
+
+    if (!keys[keyName]) {
+      keys[keyName] = 1;
+      let content = this._content;
+      let len = get(content, 'length');
+
+      addObserverForContentKey(content, keyName, this, 0, len);
+    } else {
+      keys[keyName]++;
+    }
+  }
+
+  stopObservingContentKey(keyName) {
+    let keys = this._keys;
+    if (keys && (keys[keyName] > 0) && (--keys[keyName] <= 0)) {
+      let content = this._content;
+      let len     = get(content, 'length');
+
+      removeObserverForContentKey(content, keyName, this, 0, len);
+    }
+  }
+
+  contentKeyDidChange(obj, keyName) {
+    notifyPropertyChange(this, keyName);
+  }
+}
+
+function addObserverForContentKey(content, keyName, proxy, idx, loc) {
+  while (--loc >= idx) {
+    let item = objectAt(content, loc);
+    if (item) {
+      assert(`When using @each to observe the array \`${toString(content)}\`, the array must return an object`, typeof item === 'object');
+      addObserver(item, keyName, proxy, 'contentKeyDidChange');
+    }
+  }
+}
+
+function removeObserverForContentKey(content, keyName, proxy, idx, loc) {
+  while (--loc >= idx) {
+    let item = objectAt(content, loc);
+    if (item) {
+      removeObserver(item, keyName, proxy, 'contentKeyDidChange');
+    }
+  }
+}

packages/ember-metal/lib/index.d.ts

@@ -33,6 +33,8 @@ export function get(obj: any, keyName: string): any;
 
 export function set(obj: any, keyName: string, value: any, tolerant?: boolean): void;
 
+export function objectAt(arr: any, i: number): any;
+
 export function computed(...args: Array<any>): any;
 
 export function didRender(object: any, key: string, reference: any): boolean;

packages/ember-metal/lib/index.js

@@ -39,6 +39,12 @@ export {
   set,
   trySet
 } from './property_set';
+export { objectAt } from './array';
+export {
+  eachProxyFor,
+  eachProxyArrayWillChange,
+  eachProxyArrayDidChange
+} from './each_proxy';
 export {
   addListener,
   hasListeners,

packages/ember-runtime/lib/index.d.ts

@@ -18,8 +18,6 @@ export const String: {
   loc(s: string, ...args: string[]): string;
 };
 
-export function objectAt(arr: any, i: number): any;
-
 export function isEmberArray(arr: any): boolean;
 
 export function _contentFor(proxy: any): any;

packages/ember-runtime/lib/index.js

@@ -12,7 +12,6 @@ export { default as compare } from './compare';
 export { default as isEqual } from './is-equal';
 export {
   default as Array,
-  objectAt,
   isEmberArray,
   addArrayObserver,
   removeArrayObserver,