55 lines
1.3 KiB
JavaScript
55 lines
1.3 KiB
JavaScript
export default class BaseObservable {
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constructor() {
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this._handlers = new Set();
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}
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onSubscribeFirst() {
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}
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onUnsubscribeLast() {
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}
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subscribe(handler) {
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this._handlers.add(handler);
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if (this._handlers.size === 1) {
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this.onSubscribeFirst();
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}
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return () => {
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if (handler) {
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this._handlers.delete(handler);
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if (this._handlers.size === 0) {
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this.onUnsubscribeLast();
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}
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handler = null;
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}
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return null;
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};
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}
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// Add iterator over handlers here
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}
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export function tests() {
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class Collection extends BaseObservable {
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constructor() {
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super();
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this.firstSubscribeCalls = 0;
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this.firstUnsubscribeCalls = 0;
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}
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onSubscribeFirst() { this.firstSubscribeCalls += 1; }
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onUnsubscribeLast() { this.firstUnsubscribeCalls += 1; }
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}
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return {
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test_unsubscribe(assert) {
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const c = new Collection();
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const unsubscribe = c.subscribe({});
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unsubscribe();
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assert.equal(c.firstSubscribeCalls, 1);
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assert.equal(c.firstUnsubscribeCalls, 1);
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}
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}
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}
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