fabrik_utils

Every app ends up with a utils.dart holding the same handful of helpers: something that turns a DateTime into “2 hours ago”, something that converts a string to snake_case, a debouncer for the search field.

fabrik_utils is that file, written once and tested properly.

'XMLHttpRequest'.snakeCase          // 'xml_http_request'
postedAt.timeAgo                    // '2 hours ago'
formatDuration(elapsed)             // '01:23:45'

Installation

dependencies:
  fabrik_utils: ^0.2.0

import 'package:fabrik_utils/fabrik_utils.dart';

String casing

Ten casing styles, all built on the same word-splitting logic. It understands delimiters, camelCase boundaries, and acronyms:

'hello world'.titleCase       // 'Hello World'
'helloWorld'.snakeCase        // 'hello_world'
'user_name'.camelCase         // 'userName'
'http_request'.pascalCase     // 'HttpRequest'
'Hello World'.kebabCase       // 'hello-world'
'Hello World'.constantCase    // 'HELLO_WORLD'
'hello world'.dottedCase      // 'hello.world'
'hello world'.pathCase        // 'hello/world'
'hello WORLD'.sentenceCase    // 'Hello world'
'hello world'.headerCase      // 'Hello-World'

Runs of consecutive capitals are kept together, so acronyms survive:

'XMLHttpRequest'.snakeCase    // 'xml_http_request'
'APIKey'.snakeCase            // 'api_key'
'parseJSON'.camelCase         // 'parseJson'

There is also a null-safe blank check:

String? input;
input.isNullOrBlank;          // true — null, empty, or whitespace only
'   '.isNullOrBlank;          // true

Dates and times

Relative time

timeAgo reads in both directions, so it works for timestamps and for scheduled events:

postedAt.timeAgo              // '5 mins ago' · 'yesterday' · '2 months ago'
dueAt.timeAgo                 // 'in 5 mins' · 'tomorrow' · 'in 3 days'

Formatting

Named getters over intl, so you do not memorise format strings:

date.isoDate                  // '2026-06-15'
date.dayMonthYear             // '15 Jun 2026'
date.fullWithWeekday          // 'Monday, June 15, 2026'
date.shortDateTime            // 'Jun 15, 2026 11:40 PM'
date.time12Hour               // '11:40 PM'
date.hourMinute24h            // '23:40'
date.weekdayName              // 'Monday'
date.monthShort               // 'Jun'

Checks and math

date.isToday
date.isTomorrow
date.isYesterday
date.isWeekend
date.isBetween(start, end)    // inclusive

date.startOfDay               // 00:00:00.000
date.endOfDay                 // 23:59:59.999
date.startOfWeek              // midnight on the most recent Monday

Durations

formatDuration(const Duration(seconds: 3665))   // '01:01:05'
formatDuration(const Duration(minutes: 4))      // '04:00'
formatDuration(const Duration(seconds: -65))    // '-01:05'

Hours appear only when non-zero, unless you force them:

formatDuration(const Duration(seconds: 90), alwaysShowHours: true);  // '00:01:30'

For custom timer UIs where each unit is its own widget, splitDuration returns the padded components:

final (:hours, :minutes, :seconds) = splitDuration(3665);
// '01', '01', '05'

Note

Negative values are handled deliberately, since countdown timers overshoot zero. formatDuration prefixes a minus sign; splitDuration splits by magnitude and carries the sign on hours.

Debounce and throttle

The two are easy to confuse:

	Fires	Use for
Debounce	After input stops for a given duration	Search-as-you-type, autosave
Throttle	At most once per duration, immediately	Button taps, scroll handlers

Debounce

final debounce = Debounce(duration: const Duration(milliseconds: 300));

void onSearchChanged(String query) {
  debounce.add(() => performSearch(query));
}

@override
void dispose() {
  debounce.close();
  super.dispose();
}

Use maxWait when continuous input should not defer execution forever:

Debounce(
  duration: const Duration(milliseconds: 300),
  maxWait: const Duration(seconds: 2),   // runs at least every 2s while typing
);

cancel() drops a pending call without closing the debouncer, which is useful when a screen is popped mid-edit.

Throttle

final throttle = Throttle(duration: const Duration(seconds: 1));

ElevatedButton(
  onPressed: () => throttle.add(submitOrder),   // ignores rapid double taps
  child: const Text('Place order'),
);

Both expose their state as a stream, so you can drive UI from it:

throttle.listen((status) {
  setState(() => _buttonEnabled = status.isIdle);
});

Caution

Both hold timers and a stream. Call close() in dispose() to avoid leaking them.

Infinite scroll

final controller = ScrollController();

controller.addListener(() {
  if (isApproachingScrollEnd(controller) && !isLoading) {
    loadNextPage();
  }
});

The default threshold triggers at 70% of the scroll extent; pass scrollOffsetThreshold to change it. It returns false when the controller has no clients, so it is safe to call before the first layout.

API reference

StringX on String

Member	Example
titleCase	Hello World
headerCase	Hello-World
pascalCase	HelloWorld
camelCase	helloWorld
snakeCase	hello_world
constantCase	HELLO_WORLD
kebabCase	hello-world
dottedCase	hello.world
pathCase	hello/world
sentenceCase	Hello world
capitalizeFirst	Hello world

NullableStringX on String? adds isNullOrBlank.

DateTimeX on DateTime

Group	Members
Checks	isToday, isTomorrow, isYesterday, isWeekday, isWeekend, isBetween
Math	startOfDay, endOfDay, startOfWeek
Relative	timeAgo
Formatters	isoDate, isoDateTime, dayMonthYear, shortMonthDay, monthDay, fullWithWeekday, fullWithWeekdayShort, fullDateTime, shortDateTime, time12Hour, hourMinute12h, hourMinute24h, weekdayName, weekdayShort, monthFull, monthShort

Helpers

Function	Returns
formatDuration(duration, {alwaysShowHours})	String
splitDuration(totalSeconds)	({String hours, String minutes, String seconds})
isApproachingScrollEnd(controller, {scrollOffsetThreshold})	bool

Debounce<T> and Throttle<T>

Member	Description
add(fn)	Queue (debounce) or attempt (throttle) a call
debounce(fn) / throttle(fn)	Named equivalents of add
cancel()	(Debounce) Drop the pending call, stay open
close()	Cancel timers and close the stream
isIdle / isWaiting / isBusy	Current state
listen(onData)	Subscribe to status changes