throttle.js 3.19 KB
/** PURE_IMPORTS_START tslib,_innerSubscribe PURE_IMPORTS_END */
import * as tslib_1 from "tslib";
import { SimpleOuterSubscriber, innerSubscribe, SimpleInnerSubscriber } from '../innerSubscribe';
export var defaultThrottleConfig = {
    leading: true,
    trailing: false
};
export function throttle(durationSelector, config) {
    if (config === void 0) {
        config = defaultThrottleConfig;
    }
    return function (source) { return source.lift(new ThrottleOperator(durationSelector, !!config.leading, !!config.trailing)); };
}
var ThrottleOperator = /*@__PURE__*/ (function () {
    function ThrottleOperator(durationSelector, leading, trailing) {
        this.durationSelector = durationSelector;
        this.leading = leading;
        this.trailing = trailing;
    }
    ThrottleOperator.prototype.call = function (subscriber, source) {
        return source.subscribe(new ThrottleSubscriber(subscriber, this.durationSelector, this.leading, this.trailing));
    };
    return ThrottleOperator;
}());
var ThrottleSubscriber = /*@__PURE__*/ (function (_super) {
    tslib_1.__extends(ThrottleSubscriber, _super);
    function ThrottleSubscriber(destination, durationSelector, _leading, _trailing) {
        var _this = _super.call(this, destination) || this;
        _this.destination = destination;
        _this.durationSelector = durationSelector;
        _this._leading = _leading;
        _this._trailing = _trailing;
        _this._hasValue = false;
        return _this;
    }
    ThrottleSubscriber.prototype._next = function (value) {
        this._hasValue = true;
        this._sendValue = value;
        if (!this._throttled) {
            if (this._leading) {
                this.send();
            }
            else {
                this.throttle(value);
            }
        }
    };
    ThrottleSubscriber.prototype.send = function () {
        var _a = this, _hasValue = _a._hasValue, _sendValue = _a._sendValue;
        if (_hasValue) {
            this.destination.next(_sendValue);
            this.throttle(_sendValue);
        }
        this._hasValue = false;
        this._sendValue = undefined;
    };
    ThrottleSubscriber.prototype.throttle = function (value) {
        var duration = this.tryDurationSelector(value);
        if (!!duration) {
            this.add(this._throttled = innerSubscribe(duration, new SimpleInnerSubscriber(this)));
        }
    };
    ThrottleSubscriber.prototype.tryDurationSelector = function (value) {
        try {
            return this.durationSelector(value);
        }
        catch (err) {
            this.destination.error(err);
            return null;
        }
    };
    ThrottleSubscriber.prototype.throttlingDone = function () {
        var _a = this, _throttled = _a._throttled, _trailing = _a._trailing;
        if (_throttled) {
            _throttled.unsubscribe();
        }
        this._throttled = undefined;
        if (_trailing) {
            this.send();
        }
    };
    ThrottleSubscriber.prototype.notifyNext = function () {
        this.throttlingDone();
    };
    ThrottleSubscriber.prototype.notifyComplete = function () {
        this.throttlingDone();
    };
    return ThrottleSubscriber;
}(SimpleOuterSubscriber));
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