Method subscribe

src/Observable.js:246–259

(observer, ...args)

    }

    subscribe(observer, ...args) {
        if (typeof observer === "function") {
            observer = {
                next: observer,
                error: args[0],
                complete: args[1]
            };
        }
        else if (typeof observer !== "object") {
            observer = {};
        }

        return new Subscription(observer, this._subscriber);
    }

    [Symbol.observable]() { return this }