a new take on reactivity package

packages/svelte/src/reactivity/set.js

@@ -1,158 +1,16 @@
-import { DEV } from 'esm-env';
-import { source, set } from '../internal/client/reactivity/sources.js';
-import { get } from '../internal/client/runtime.js';
-import { map } from './utils.js';
-
-var read_methods = ['forEach', 'isDisjointFrom', 'isSubsetOf', 'isSupersetOf'];
-var set_like_methods = ['difference', 'intersection', 'symmetricDifference', 'union'];
-
-var inited = false;
-
-/**
- * @template T
- * @extends {Set<T>}
- */
-export class ReactiveSet extends Set {
-	/** @type {Map<T, import('#client').Source<boolean>>} */
-	#sources = new Map();
-	#version = source(0);
-	#size = source(0);
-
-	/**
-	 * @param {Iterable<T> | null | undefined} [value]
-	 */
-	constructor(value) {
-		super();
-
-		// If the value is invalid then the native exception will fire here
-		if (DEV) new Set(value);
-
-		if (value) {
-			var sources = this.#sources;
-
-			for (var element of value) {
-				sources.set(element, source(true));
-			}
-
-			this.#size.v = sources.size;
+import { make_reactive } from './utils.js';
+
+export const ReactiveSet = make_reactive(Set, {
+	mutation_properties: /** @type {const} */ (['add', 'clear', 'delete']),
+	interceptors: {
+		add: (value, property, ...params) => {
+			return !value.has(params[0]);
+		},
+		clear: (value, property, ...params) => {
+			return value.size !== 0;
+		},
+		delete: (value, property, ...params) => {
+			return !value.has(params[0]);
 		}
-
-		if (!inited) this.#init();
-	}
-
-	// We init as part of the first instance so that we can treeshake this class
-	#init() {
-		inited = true;
-
-		var proto = ReactiveSet.prototype;
-		var set_proto = Set.prototype;
-
-		for (const method of read_methods) {
-			// @ts-ignore
-			proto[method] = function (...v) {
-				get(this.#version);
-				// We don't populate the underlying Set, so we need to create a clone using
-				// our internal values and then pass that to the method.
-				var clone = new Set(this.values());
-				// @ts-ignore
-				return set_proto[method].apply(clone, v);
-			};
-		}
-
-		for (const method of set_like_methods) {
-			// @ts-ignore
-			proto[method] = function (...v) {
-				get(this.#version);
-				// We don't populate the underlying Set, so we need to create a clone using
-				// our internal values and then pass that to the method.
-				var clone = new Set(this.values());
-				// @ts-ignore
-				var set = /** @type {Set<T>} */ (set_proto[method].apply(clone, v));
-				return new ReactiveSet(set);
-			};
-		}
-	}
-
-	#increment_version() {
-		set(this.#version, this.#version.v + 1);
-	}
-
-	/** @param {T} value */
-	has(value) {
-		var s = this.#sources.get(value);
-
-		if (s === undefined) {
-			// We should always track the version in case
-			// the Set ever gets this value in the future.
-			get(this.#version);
-
-			return false;
-		}
-
-		return get(s);
-	}
-
-	/** @param {T} value */
-	add(value) {
-		var sources = this.#sources;
-
-		if (!sources.has(value)) {
-			sources.set(value, source(true));
-			set(this.#size, sources.size);
-			this.#increment_version();
-		}
-
-		return this;
-	}
-
-	/** @param {T} value */
-	delete(value) {
-		var sources = this.#sources;
-		var s = sources.get(value);
-
-		if (s !== undefined) {
-			var removed = sources.delete(value);
-			set(this.#size, sources.size);
-			set(s, false);
-			this.#increment_version();
-			return removed;
-		}
-
-		return false;
-	}
-
-	clear() {
-		var sources = this.#sources;
-
-		if (sources.size !== 0) {
-			set(this.#size, 0);
-			for (var s of sources.values()) {
-				set(s, false);
-			}
-			this.#increment_version();
-		}
-
-		sources.clear();
-	}
-
-	keys() {
-		get(this.#version);
-		return map(this.#sources.keys(), (key) => key, 'Set Iterator');
-	}
-
-	values() {
-		return this.keys();
-	}
-
-	entries() {
-		return map(this.keys(), (key) => /** @type {[T, T]} */ ([key, key]), 'Set Iterator');
-	}
-
-	[Symbol.iterator]() {
-		return this.keys();
-	}
-
-	get size() {
-		return get(this.#size);
 	}
-}
+});

packages/svelte/src/reactivity/utils.js

@@ -1,3 +1,6 @@
+import { source, set } from '../internal/client/reactivity/sources.js';
+import { get } from '../internal/client/runtime.js';
+
 /**
  * @template T
  * @template U
@@ -27,3 +30,84 @@ export function map(iterable, fn, name) {
 function get_this() {
 	return this;
 }
+
+/**
+ * @template TEntityInstance
+ * @template {(keyof TEntityInstance)[]} TMutationProperties
+ * @typedef {Record<TMutationProperties[number], (value: TEntityInstance, property: TMutationProperties[number], ...params: any[])=>boolean>}  Interceptors - return false if you want to prevent reactivity for this call/get
+ */
+
+/**
+ * @template TEntityInstance
+ * @template {(keyof TEntityInstance)[]} TMutationProperties
+ * @typedef {object} Options
+ * @prop {TMutationProperties} mutation_properties - an array of property names on `TEntityInstance`. when calling a property on `TEntityInstance`, if the property name exists in this array, then mentioned property is made reactive.
+ * @prop {Interceptors<TEntityInstance, TMutationProperties>} [interceptors={}] - if the property names in `mutation_properties` shouldn't be always reactive, such calling `set.add(2)` twice, you can prevent the reactivity by returning false from these interceptors
+ */
+
+/**
+ * @template {new (...args: any) => any} TEntity - the entity we want to make reactive
+ * @template {(keyof InstanceType<TEntity>)[]} TMutationProperties
+ * @param {TEntity} Entity - the class/function we want to make reactive
+ * @param {Options<InstanceType<TEntity>, TMutationProperties>} options - configurations for how reactivity works for this entity
+ * @returns {TEntity}
+ */
+export const make_reactive = (Entity, options) => {
+	/**
+	 * @template {InstanceType<TEntity>} TEntityInstance
+	 * @template {keyof TEntityInstance} TProperty
+	 * @param {import('#client').Source<number>} target
+	 * @param {TProperty} property
+	 * @param {TEntityInstance} entity_instance
+	 * @param {TEntityInstance[TProperty] extends (...args: any)=>any ? Parameters<TEntityInstance[TProperty]>: never} params
+	 */
+	function notify_if_required(target, property, entity_instance, ...params) {
+		if (options.interceptors?.[property]?.(entity_instance, property, ...params) === false) {
+			// if interceptor said to not make this call reactive then bailout
+			return;
+		}
+
+		if (options.mutation_properties.some((v) => v === property)) {
+			set(target, target.v + 1);
+		} else {
+			get(target);
+		}
+	}
+
+	/**
+	 * @template {ConstructorParameters<TEntity>} TParams
+	 */
+	// we return a class so that the caller can call it with new
+	// @ts-ignore
+	return class {
+		/**
+		 * @param {TParams}  params
+		 * @returns
+		 */
+		constructor(...params) {
+			const sig = source(0);
+
+			return new Proxy(new Entity(...params), {
+				get(target, property) {
+					const orig_property = target[property];
+
+					let result;
+
+					if (typeof orig_property === 'function') {
+						// Bind functions directly to the Set
+						result = ((/** @type {any} */ ...params) => {
+							notify_if_required(sig, property, target, ...params);
+							return orig_property.bind(target)(...params);
+						}).bind(target);
+					} else {
+						// Properly handle getters
+						result = Reflect.get(target, property, target);
+						notify_if_required(sig, property, target);
+					}
+
+					return result;
+				}
+			});
+		}
+	};
+};