SystemFormatStyle.Stopwatch

A format style that displays elapsed time as a precision stopwatch counting up from zero.

Declaration

struct Stopwatch

Overview

Stopwatch produces output in a time-pattern format that includes hundredths of a second by default, making it suitable for use cases such as athletic timing where sub-second precision matters.

let startDate = Date.now
Text(.currentDate, format: .stopwatch(startingAt: startDate))
// Output: "00:05.23" (after 5.23 seconds)

Output format progression

The stopwatch automatically adds an hours field when the elapsed time reaches one hour:

Elapsed	Output
Under 1 min	`00:05.23`
Under 1 hour	`45:30.12`
1 hour or more	`01:00:00.00`
Over 25 hours	`25:01:01.00`

Adjusting precision

Control the displayed precision with the maxPrecision parameter:

// Whole-second precision (no fractional digits)
.stopwatch(startingAt: start, maxPrecision: .seconds(1))
// Output: "01:23"

// Tenth-of-a-second precision (one fractional digit)
.stopwatch(startingAt: start, maxPrecision: .milliseconds(100))
// Output: "01:23.4"

// Minute-only precision
.stopwatch(startingAt: start, maxPrecision: .seconds(60))
// Output: "1 hour" or "23 minutes"

Controlling field count

The maxFieldCount parameter limits how many fields appear:

// At 1 hour, 23 minutes, 45.67 seconds elapsed:
// maxFieldCount: 4 (default): "01:23:45.67"
// maxFieldCount: 3: "01:23:45"
// maxFieldCount: 2: "1:23" (hours and minutes only)

Topics

Initializers

init(startingAt:showsHours:maxFieldCount:maxPrecision:)