90 lines
2.1 KiB
TypeScript
90 lines
2.1 KiB
TypeScript
enum ResolvableState {
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WAITING,
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PENDING,
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ERROR,
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DONE
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}
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class FetchOnce<T, U extends Array<unknown>> {
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protected data: T|undefined;
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protected error: unknown|undefined;
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protected state: ResolvableState = ResolvableState.WAITING;
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protected pendings: [(res: Promise<T>|T) => void, (reason: unknown) => void][] = [];
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constructor(protected fetchMethod?: (...args: U) => Promise<T>) { }
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public reset(): void {
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this.data = undefined;
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this.error = undefined;
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this.state = ResolvableState.WAITING;
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}
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public resolve(...args: U): Promise<T> {
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return new Promise((resolve, reject) => {
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switch (this.state) {
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case ResolvableState.WAITING:
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this.state = ResolvableState.PENDING;
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this.pendings.push([resolve, reject]);
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if (this.fetchMethod) this.parsePromise(this.fetchMethod(...args));
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break;
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case ResolvableState.PENDING:
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this.pendings.push([resolve, reject]);
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break;
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case ResolvableState.DONE:
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resolve(this.data);
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break;
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case ResolvableState.ERROR:
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reject(this.error);
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break;
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}
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});
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}
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protected isFinished(): boolean {
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return this.state === ResolvableState.DONE || this.state === ResolvableState.ERROR;
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}
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protected parsePromise(promise: Promise<T>): void {
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promise.then((data) => {
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this.data = data;
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this.state = ResolvableState.DONE;
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this.pendings.forEach(pending => pending[0](data));
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}).catch(err => {
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this.error = err;
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this.state = ResolvableState.ERROR;
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this.pendings.forEach(pending => pending[1](err));
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});
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}
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}
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export class Resolvable<T, U extends Array<unknown>> extends FetchOnce<T, U> {
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constructor(fetchMethod: (...args: U) => Promise<T>) {
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super(fetchMethod);
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}
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}
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export class WaitForSync<T> extends FetchOnce<T, never> {
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protected state: ResolvableState = ResolvableState.PENDING;
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constructor() {
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super(undefined);
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}
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public setData(data: T): void {
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if (!this.isFinished()) {
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this.parsePromise((async () => data)());
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}
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}
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public setError(error: unknown): void {
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if (!this.isFinished()) {
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this.parsePromise((async () => { throw error; })());
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}
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}
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public reset(): void {
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super.reset();
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this.state = ResolvableState.PENDING;
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}
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}
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