skipLast.js 2.37 KB
"use strict";
var __extends = (this && this.__extends) || (function () {
    var extendStatics = function (d, b) {
        extendStatics = Object.setPrototypeOf ||
            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
            function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
        return extendStatics(d, b);
    }
    return function (d, b) {
        extendStatics(d, b);
        function __() { this.constructor = d; }
        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
    };
})();
Object.defineProperty(exports, "__esModule", { value: true });
var Subscriber_1 = require("../Subscriber");
var ArgumentOutOfRangeError_1 = require("../util/ArgumentOutOfRangeError");
function skipLast(count) {
    return function (source) { return source.lift(new SkipLastOperator(count)); };
}
exports.skipLast = skipLast;
var SkipLastOperator = (function () {
    function SkipLastOperator(_skipCount) {
        this._skipCount = _skipCount;
        if (this._skipCount < 0) {
            throw new ArgumentOutOfRangeError_1.ArgumentOutOfRangeError;
        }
    }
    SkipLastOperator.prototype.call = function (subscriber, source) {
        if (this._skipCount === 0) {
            return source.subscribe(new Subscriber_1.Subscriber(subscriber));
        }
        else {
            return source.subscribe(new SkipLastSubscriber(subscriber, this._skipCount));
        }
    };
    return SkipLastOperator;
}());
var SkipLastSubscriber = (function (_super) {
    __extends(SkipLastSubscriber, _super);
    function SkipLastSubscriber(destination, _skipCount) {
        var _this = _super.call(this, destination) || this;
        _this._skipCount = _skipCount;
        _this._count = 0;
        _this._ring = new Array(_skipCount);
        return _this;
    }
    SkipLastSubscriber.prototype._next = function (value) {
        var skipCount = this._skipCount;
        var count = this._count++;
        if (count < skipCount) {
            this._ring[count] = value;
        }
        else {
            var currentIndex = count % skipCount;
            var ring = this._ring;
            var oldValue = ring[currentIndex];
            ring[currentIndex] = value;
            this.destination.next(oldValue);
        }
    };
    return SkipLastSubscriber;
}(Subscriber_1.Subscriber));
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