Change SubscriptionFilters to extend Set

packages/lib/src/subscriptions.ts

@@ -14,25 +14,27 @@ export type EventSubscriberCallback<T> = (event: T | null, synced: boolean) => v
  * When isEmpty() is true, no strings match this filter.
  * Otherwise, literal string matching is performed against a set.
  */
-export class SubscriptionFilters {
+export class SubscriptionFilters extends Set<string> {
 	private constructor(
 		private _all: boolean,
-		private _filters: Set<string>,
-	) {}
+		_filters: Iterable<string> = [],
+	) {
+		super(_filters);
+	}
 
 	static jsonSchema = Type.Array(Type.String());
 
 	static fromJSON(json: Static<typeof this.jsonSchema>) {
-		return new this(false, new Set(json));
+		return new this(false, json);
 	}
 
 	toJSON() {
-		return [...this._filters];
+		return [...this];
 	}
 
 	/** Creates a subscription filter accepting all strings */
 	static all() {
-		return new this(true, new Set());
+		return new this(true);
 	}
 
 	isAll() {
@@ -41,11 +43,11 @@ export class SubscriptionFilters {
 
 	/** Creates a subscription filter rejecting all strings */
 	static empty() {
-		return new this(false, new Set());
+		return new this(false);
 	}
 
 	isEmpty() {
-		return !this._all && this._filters.size === 0;
+		return !this._all && this.size === 0;
 	}
 
 	/**
@@ -67,20 +69,20 @@ export class SubscriptionFilters {
 		if (this._all) {
 			return "[SubscriptionFilters All]";
 		}
-		if (this._filters.size === 0) {
+		if (this.size === 0) {
 			return "[SubscriptionFilters Empty]";
 		}
-		return `[SubscriptionFilters Set<${this._filters.size}>]`;
+		return `[SubscriptionFilters Set<${this.size}>]`;
 	}
 
 	/** Returns true if this filter accepts the given string */
 	accepts(value: string) {
-		return this._all || this._filters.has(value);
+		return this._all || this.has(value);
 	}
 
 	/** Returns true if this filter extends the other */
 	extends(other: this) {
-		return this._all || (!other._all && [...other._filters.values()].every(value => this._filters.has(value)));
+		return this._all || (!other._all && [...other.values()].every(value => this.has(value)));
 	}
 
 	/** Returns true if there is overlap between two filters */
@@ -91,8 +93,8 @@ export class SubscriptionFilters {
 		if (other._all) {
 			return !this.isEmpty();
 		}
-		for (const filter of other._filters) {
-			if (this._filters.has(filter)) {
+		for (const filter of other) {
+			if (this.has(filter)) {
 				return true;
 			}
 		}
@@ -106,11 +108,11 @@ export class SubscriptionFilters {
 		}
 		if (other._all) {
 			this._all = true;
-			this._filters.clear();
+			this.clear();
 			return;
 		}
-		for (const filter of other._filters) {
-			this._filters.add(filter);
+		for (const filter of other) {
+			this.add(filter);
 		}
 	}
 
@@ -122,14 +124,14 @@ export class SubscriptionFilters {
 	subtract(other: this) {
 		if (other._all) {
 			this._all = false;
-			this._filters.clear();
+			this.clear();
 			return;
 		}
 		if (this._all) {
 			return; // Cannot subtract from all
 		}
-		for (const filter of other._filters) {
-			this._filters.delete(filter);
+		for (const filter of other) {
+			this.delete(filter);
 		}
 	}
 }