generate.js 3.39 KB
import { Observable } from '../Observable';
import { identity } from '../util/identity';
import { isScheduler } from '../util/isScheduler';
export function generate(initialStateOrOptions, condition, iterate, resultSelectorOrObservable, scheduler) {
    let resultSelector;
    let initialState;
    if (arguments.length == 1) {
        const options = initialStateOrOptions;
        initialState = options.initialState;
        condition = options.condition;
        iterate = options.iterate;
        resultSelector = options.resultSelector || identity;
        scheduler = options.scheduler;
    }
    else if (resultSelectorOrObservable === undefined || isScheduler(resultSelectorOrObservable)) {
        initialState = initialStateOrOptions;
        resultSelector = identity;
        scheduler = resultSelectorOrObservable;
    }
    else {
        initialState = initialStateOrOptions;
        resultSelector = resultSelectorOrObservable;
    }
    return new Observable(subscriber => {
        let state = initialState;
        if (scheduler) {
            return scheduler.schedule(dispatch, 0, {
                subscriber,
                iterate,
                condition,
                resultSelector,
                state
            });
        }
        do {
            if (condition) {
                let conditionResult;
                try {
                    conditionResult = condition(state);
                }
                catch (err) {
                    subscriber.error(err);
                    return undefined;
                }
                if (!conditionResult) {
                    subscriber.complete();
                    break;
                }
            }
            let value;
            try {
                value = resultSelector(state);
            }
            catch (err) {
                subscriber.error(err);
                return undefined;
            }
            subscriber.next(value);
            if (subscriber.closed) {
                break;
            }
            try {
                state = iterate(state);
            }
            catch (err) {
                subscriber.error(err);
                return undefined;
            }
        } while (true);
        return undefined;
    });
}
function dispatch(state) {
    const { subscriber, condition } = state;
    if (subscriber.closed) {
        return undefined;
    }
    if (state.needIterate) {
        try {
            state.state = state.iterate(state.state);
        }
        catch (err) {
            subscriber.error(err);
            return undefined;
        }
    }
    else {
        state.needIterate = true;
    }
    if (condition) {
        let conditionResult;
        try {
            conditionResult = condition(state.state);
        }
        catch (err) {
            subscriber.error(err);
            return undefined;
        }
        if (!conditionResult) {
            subscriber.complete();
            return undefined;
        }
        if (subscriber.closed) {
            return undefined;
        }
    }
    let value;
    try {
        value = state.resultSelector(state.state);
    }
    catch (err) {
        subscriber.error(err);
        return undefined;
    }
    if (subscriber.closed) {
        return undefined;
    }
    subscriber.next(value);
    if (subscriber.closed) {
        return undefined;
    }
    return this.schedule(state);
}
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