Mergin better performance branch

2026-02-27 18:54:44 +08:00 · 2022-09-04 14:33:22 +02:00
parent 47c15fbf8d
commit 715dee6a5a
97 changed files with 2725 additions and 2833 deletions
--- a/js/Observable.js
+++ b/js/Observable.js
@@ -0,0 +1,105 @@
+export default class Observable {
+
+    /** @type {Map<String, Object[]>} */
+    #observers = new Map()
+
+    /**
+     * @param {String} property
+     * @param {(value: any) => {}} observer
+     */
+    subscribe(property, observer) {
+        let observers = this.#observers
+        if (observers.has(property)) {
+            let propertyObservers = observers.get(property)
+            if (propertyObservers.includes(observer)) {
+                return false
+            } else {
+                propertyObservers.push(observer)
+            }
+        } else {
+            let fromPrototype = false
+            let propertyDescriptor = Object.getOwnPropertyDescriptor(this, property)
+            if (!propertyDescriptor) {
+                fromPrototype = true
+                propertyDescriptor = Object.getOwnPropertyDescriptor(Object.getPrototypeOf(this), property) ?? {}
+                if (!propertyDescriptor) {
+                    return false
+                }
+            }
+            observers.set(property, [observer])
+            const isValue = "value" in propertyDescriptor
+            const hasSetter = "set" in propertyDescriptor
+            if (!(isValue || hasSetter)) {
+                throw new Error(`Property ${property} is not a value or a setter`)
+            }
+            // A Symbol so it does not show up in Object.getOwnPropertyNames()
+            const storageKey = Symbol.for(property + "Storage")
+            const valInfoKey = Symbol.for(property + "ValInfo")
+            Object.defineProperties(
+                fromPrototype ? Object.getPrototypeOf(this) : this,
+                {
+                    [storageKey]: {
+                        configurable: true,
+                        enumerable: false, // Non enumerable so it does not show up in for...in or Object.keys()
+                        ...(isValue
+                            ? {
+                                value: this[property],
+                                writable: true,
+                            }
+                            : {
+                                get: propertyDescriptor.get,
+                                set: propertyDescriptor.set,
+                            }
+                        )
+                    },
+                    [valInfoKey]: {
+                        configurable: true,
+                        enumerable: false,
+                        value: [fromPrototype, isValue]
+                    },
+                    [property]: {
+                        configurable: true,
+                        ...(isValue && {
+                            get() {
+                                return this[storageKey]
+                            }
+                        }),
+                        set(v) {
+                            this[storageKey] = v
+                            observers.get(property).forEach(observer => {
+                                observer(this[property])
+                            })
+                        },
+                    }
+                }
+            )
+        }
+        return true
+    }
+
+    /**
+     * @param {String} property
+     * @param {Object} observer
+     */
+    unsubscribe(property, observer) {
+        let observers = this.#observers.get(property)
+        if (!observers?.includes(observer)) {
+            return false
+        }
+        observers.splice(observers.indexOf(observer), 1)
+        if (observers.length == 0) {
+            const storageKey = Symbol.for(property + "Storage")
+            const valInfoKey = Symbol.for(property + "ValInfo")
+            const fromPrototype = this[valInfoKey][0]
+            const isValue = this[valInfoKey][1]
+            Object.defineProperty(
+                fromPrototype ? Object.getPrototypeOf(this) : this,
+                property,
+                Object.getOwnPropertyDescriptor(fromPrototype ? Object.getPrototypeOf(this) : this, storageKey),
+            )
+            delete this[valInfoKey]
+            delete this[storageKey]
+        }
+        return true
+    }
+}