98 lines
2.6 KiB
TypeScript
98 lines
2.6 KiB
TypeScript
import { ISubscription } from "./Publisher";
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class CapsuleSubscription implements ISubscription {
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private unbindCallback?: () => void;
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constructor(unbindCallback: () => void) {
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this.unbindCallback = unbindCallback;
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}
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unbind(): void {
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this.unbindCallback?.();
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}
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}
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interface Stringable {
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toString(): string;
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}
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type Captable = Stringable | string | null;
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export type MaybeCapsule<T> = T | Capsule<T>;
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export default class Capsule<T extends Captable = Captable> {
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private watchers: Array<(newVal: T) => void> | null = null;
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private afterWatchers: Array<(newVal: T) => void> | null = null;
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private value: T;
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private asString?: string;
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private isString: boolean;
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private constructor(val: T) {
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this.value = val;
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this.isString = typeof val === "string";
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}
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static new<T extends Captable>(val: MaybeCapsule<T>): Capsule<T> {
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if (val instanceof Capsule) {
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return val;
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} else {
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return new Capsule<T>(val);
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}
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}
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watch(watcher: (newVal: T) => void, after?: boolean): ISubscription {
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if (after) {
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if (this.afterWatchers === null) {
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this.afterWatchers = [];
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}
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this.afterWatchers.push(watcher);
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} else {
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if (this.watchers === null) {
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this.watchers = [];
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}
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this.watchers.push(watcher);
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}
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return new CapsuleSubscription(() => this.unbind(watcher, !!after));
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}
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private unbind(watcher: (newVal: T) => void, after: boolean): void {
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if (after) {
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if (!this.afterWatchers) {
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return;
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}
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const index = this.afterWatchers.indexOf(watcher);
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if (index !== -1) {
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this.afterWatchers.splice(index, 1);
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}
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} else {
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if (!this.watchers) {
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return;
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}
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const index = this.watchers.indexOf(watcher);
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if (index !== -1) {
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this.watchers.splice(index, 1);
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}
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}
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}
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get val(): T {
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return this.value;
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}
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set val(val: T) {
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this.watchers?.forEach(watcher => watcher(val));
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this.value = val;
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this.afterWatchers?.forEach(watcher => watcher(val));
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}
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toString(): string {
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if (!this.asString) {
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if (this.isString) {
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return this.val as unknown as string;
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} else {
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this.asString = this.val?.toString() ?? "null";
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}
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}
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return this.asString;
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}
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}
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