Automatically Unsubscribe in Angular Component

let isFunction = fn => typeof fn === "function";

const doUnsubscribe = subscription => {

subscription &&

isFunction(subscription.unsubscribe) &&

subscription.unsubscribe();

};

const doUnsubscribeIfArray = subscriptionsArray => {

Array.isArray(subscriptionsArray) &&

subscriptionsArray.forEach(doUnsubscribe);

};

export function AutoUnsubscribe({

blackList = [],

arrayName = "",

event = "ngOnDestroy"

} = {}) {

return function(constructor: Function) {

const original = constructor.prototype[event];

if (!isFunction(original)) {

throw new Error(

`${

constructor.name

} is using @AutoUnsubscribe but does not implement ${event}`

);

}

constructor.prototype[event] = function() {

isFunction(original) && original.apply(this, arguments);

if (arrayName) {

doUnsubscribeIfArray(this[arrayName]);

return;

}

for (let propName in this) {

if (blackList.includes(propName)) continue;

const property = this[propName];

doUnsubscribe(property);

}

};

};

} 

//@AutoUnsubscribe() // use if direct property

@AutoUnsubscribe({ // use if you have array of subscriptions

arrayName:"subscriptions"

})

@Component({

selector: 'inbox'

})

export class InboxComponent {

one: Subscription;

two: Subscription;

subscription: [];

constructor( private store: Store<any>, private element : ElementRef ) {}

ngOnInit() {

this.one = store.select("data").subscribe(data => // do something);

this.two = Observable.interval.subscribe(data => // do something);

// this.subscriptions = [

// onResizeSubscription,

// deploymentSubscription,

// patientIdSubscription,

// createQuestionnaireLoadedSubscription,

// errorCreateQeustionnaireSubscription,

// ];

}

// This method must be present, even if empty.

ngOnDestroy() {

// We'll throw an error if it doesn't

}

}