no-ignored-subscription.md

Use returned subscriptions (no-ignored-subscription)

The effects failures if an subscription returned by call to subscribe is neither assigned to a variable or property or passed to a function.

Rule details

Examples of incorrect code for this rule:

interval(1e3).subscribe(
  (value) => console.log(value)
);

Examples of correct code for this rule:

const subscription = interval(1e3).subscribe(
  (value) => console.log(value)
);

When subscribers are passed to subscribe they are chained, so the returned subscription can be ignored:

const numbers = new Observable<number>(subscriber => {
  interval(1e3).subscribe(subscriber);
});

Options

This rule has no options.