Observable.js 3.23 KB
import { canReportError } from './util/canReportError';
import { toSubscriber } from './util/toSubscriber';
import { observable as Symbol_observable } from './symbol/observable';
import { pipeFromArray } from './util/pipe';
import { config } from './config';
export class Observable {
    constructor(subscribe) {
        this._isScalar = false;
        if (subscribe) {
            this._subscribe = subscribe;
        }
    }
    lift(operator) {
        const observable = new Observable();
        observable.source = this;
        observable.operator = operator;
        return observable;
    }
    subscribe(observerOrNext, error, complete) {
        const { operator } = this;
        const sink = toSubscriber(observerOrNext, error, complete);
        if (operator) {
            sink.add(operator.call(sink, this.source));
        }
        else {
            sink.add(this.source || (config.useDeprecatedSynchronousErrorHandling && !sink.syncErrorThrowable) ?
                this._subscribe(sink) :
                this._trySubscribe(sink));
        }
        if (config.useDeprecatedSynchronousErrorHandling) {
            if (sink.syncErrorThrowable) {
                sink.syncErrorThrowable = false;
                if (sink.syncErrorThrown) {
                    throw sink.syncErrorValue;
                }
            }
        }
        return sink;
    }
    _trySubscribe(sink) {
        try {
            return this._subscribe(sink);
        }
        catch (err) {
            if (config.useDeprecatedSynchronousErrorHandling) {
                sink.syncErrorThrown = true;
                sink.syncErrorValue = err;
            }
            if (canReportError(sink)) {
                sink.error(err);
            }
            else {
                console.warn(err);
            }
        }
    }
    forEach(next, promiseCtor) {
        promiseCtor = getPromiseCtor(promiseCtor);
        return new promiseCtor((resolve, reject) => {
            let subscription;
            subscription = this.subscribe((value) => {
                try {
                    next(value);
                }
                catch (err) {
                    reject(err);
                    if (subscription) {
                        subscription.unsubscribe();
                    }
                }
            }, reject, resolve);
        });
    }
    _subscribe(subscriber) {
        const { source } = this;
        return source && source.subscribe(subscriber);
    }
    [Symbol_observable]() {
        return this;
    }
    pipe(...operations) {
        if (operations.length === 0) {
            return this;
        }
        return pipeFromArray(operations)(this);
    }
    toPromise(promiseCtor) {
        promiseCtor = getPromiseCtor(promiseCtor);
        return new promiseCtor((resolve, reject) => {
            let value;
            this.subscribe((x) => value = x, (err) => reject(err), () => resolve(value));
        });
    }
}
Observable.create = (subscribe) => {
    return new Observable(subscribe);
};
function getPromiseCtor(promiseCtor) {
    if (!promiseCtor) {
        promiseCtor = config.Promise || Promise;
    }
    if (!promiseCtor) {
        throw new Error('no Promise impl found');
    }
    return promiseCtor;
}
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