---
title: "publish(every:tolerance:on:in:options:)"
framework: foundation
role: symbol
role_heading: Type Method
path: "foundation/timer/publish(every:tolerance:on:in:options:)"
---

# publish(every:tolerance:on:in:options:)

Returns a publisher that repeatedly emits the current date on the given interval.

## Declaration

```swift
static func publish(every interval: TimeInterval, tolerance: TimeInterval? = nil, on runLoop: RunLoop, in mode: RunLoop.Mode, options: RunLoop.SchedulerOptions? = nil) -> Timer.TimerPublisher
```

## Parameters

- `interval`: The time interval on which to publish events. For example, a value of 0.5 publishes an event approximately every half-second.
- `tolerance`: The allowed timing variance when emitting events. Defaults to nil, which allows any variance.
- `runLoop`: The run loop on which the timer runs.
- `mode`: The run loop mode in which to run the timer.
- `options`: Scheduler options passed to the timer. Defaults to nil.

## Return Value

Return Value A publisher that repeatedly emits the current date on the given interval.

## Discussion

Discussion The return type, Timer.TimerPublisher, conforms to ConnectablePublisher, which means you must explicitly connect to the Timer publisher to begin publishing events. You can do this with a call to connect(), or by using autoconnect() to automatically connect when a subscriber attaches, as shown here: cancellable = Timer.publish(every: 1, on: .main, in: .common)     .autoconnect()     .sink() {         print ("timer fired: \($0)") }

## Topics

### Creating a Timer Publisher

- [init(interval:tolerance:runLoop:mode:options:)](foundation/timer/timerpublisher/init(interval:tolerance:runloop:mode:options:).md)

## See Also

### Firing Messages as a Combine Publisher

- [Timer.TimerPublisher](foundation/timer/timerpublisher.md)