当我误用interval Observable时,如何释放内存?

class BigClass {
    constructor(observable) {
        this.bigArray = new Array(9999999).fill(0);
        observable.subscribe(x => this.result = x);
    }
    //...
}

let observable = new rxjs.interval(1000);
let bigObject = new BigClass(observable);
let bigObject1 = new BigClass(observable);
let bigObject2 = new BigClass(observable);
let bigObject3 = new BigClass(observable);

bigObject = null;
bigObject1 = null;
bigObject2 = null;
bigObject3 = null;
observable = null;

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