Feature Request: ngOnDestroy for Observable Subscriptions

[danielzen]

Some might need a reminder by tslint, to remind us in the console that our components or directives should have a ngOnDestroy method when it detects none.
We can add a custom rule to tslint to warn us in the console during linting and building if it finds no ngOnDestroy hook in our components:

Item #6 contains the code:
https://blog.bitsrc.io/6-ways-to-unsubscribe-from-observables-in-angular-ab912819a78f

[macjohnny]

@danielzen thanks for your request.

whenever an observable is subscribed to within a component, the angular-rxjs-takeuntil-before-subscribe rule ensures that there is an ngOnDestroy method

lint-rules/rules/angularRxjsTakeuntilBeforeSubscribeRule.ts

Lines 195 to 216 in eafe305

	// check the ngOnDestroyMethod
	const destroySubjectNamesUsedList = Object.keys(destroySubjectNamesUsed);
	destroySubjectNamesUsedList.forEach(destroySubjectNameUsed => {
	// look for ngOnDestroy in class and in all parent classes
	const classesToCheck = [
	componentClassDeclaration,
	...this.findParentClasses(program, componentClassDeclaration)
	];
	const ngOnDestroyFailuresList = classesToCheck.map(classDeclaration => this.checkNgOnDestroy(
	sourceFile,
	classDeclaration,
	destroySubjectNameUsed
	));
	// if there is no correct implementation of ngOnDestroy in any of the classes to be checked
	if (ngOnDestroyFailuresList.length > 0 && !ngOnDestroyFailuresList.find(failures => failures.length === 0)) {
	failures.push(...ngOnDestroyFailuresList[0]);
	}
	});
	return failures;
	}

lint-rules/rules/angularRxjsTakeuntilBeforeSubscribeRule.ts

Lines 417 to 424 in eafe305

	/**
	* Checks whether the class implements an ngOnDestroy method and invokes .next() on the destroy subjects
	*/
	private checkNgOnDestroy(
	sourceFile: ts.SourceFile,
	classDeclaration: ts.ClassDeclaration,
	destroySubjectNameUsed: string
	): Lint.RuleFailure[] {

how is your feature request different from that?

[danielzen]

Not sure why it didn't work for me, but I will double check. Thanks!