forked from mystiq/hydrogen-web
utility: turn observable value into observable map with one K,V pair
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1 changed files with 53 additions and 0 deletions
53
src/observable/map/ObservableValueMap.ts
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53
src/observable/map/ObservableValueMap.ts
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/*
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Copyright 2022 The Matrix.org Foundation C.I.C.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import {BaseObservableMap} from "./BaseObservableMap";
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import {BaseObservableValue} from "../value/BaseObservableValue";
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import {SubscriptionHandle} from "../BaseObservable";
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export class ObservableValueMap<K, V> extends BaseObservableMap<K, V> {
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private subscription?: SubscriptionHandle;
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constructor(private readonly key: K, private readonly observableValue: BaseObservableValue<V>) {
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super();
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}
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onSubscribeFirst() {
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this.subscription = this.observableValue.subscribe(value => {
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this.emitUpdate(this.key, value, undefined);
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});
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super.onSubscribeFirst();
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}
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onUnsubscribeLast() {
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this.subscription!();
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super.onUnsubscribeLast();
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}
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*[Symbol.iterator](): Iterator<[K, V]> {
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yield [this.key, this.observableValue.get()];
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}
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get size(): number {
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return 1;
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}
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get(key: K): V | undefined {
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if (key == this.key) {
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return this.observableValue.get();
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}
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}
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}
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