Table of Contents

• Installation
• Quick Start
• Extension Collections
  • Object
  • String
  • Number & Int
  • Double
  • DateTime
  • Duration
  • Iterable
  • List
  • Map
  • Color
  • BuildContext
  • Widget
  • TextStyle
  • Icon
  • Image
  • File
  • EdgeInsets
  • State
  • Platform
  • Navigation
  • Alert & Snackbar
  • Form Validators
• Examples
• Contributing
• License

---

Installation

Add the package to your pubspec.yaml:

dependencies:
  extensions_core: ^0.1.0

Then run:

flutter pub get

Requirements: Dart ^3.6.0 · Flutter >=3.27.0

---

Quick Start

import 'package:extensions_core/extensions.dart';

void main() {
  // Strings
  'hello world'.toCamelCase();      // helloWorld
  'hello world'.toSnakeCase();      // hello_world
  'user@site.com'.isEmail();        // true

  // Iterables
  [1, 2, 3, 4].sum;                 // 10
  [1, 2, 3].zip(['a', 'b']);        // [(1, a), (2, b)]

  // Colors
  colorFromHex('#2196f3').toHex();  // #ff2196f3

  // Dates
  DateTime.now().startOfWeek;       // Monday
}

---

Extension Collections

Object

Extension	Description
let<R>(R Function(T))	Pass this to a function, return its result.
also(void Function(T))	Run a side effect, return this.
run<R>(R Function(T))	Alias of let.
isNull / isNotNull	Null checks on any nullable value.

final length = 'hello'.let((s) => s.length); // 5
String? maybe;
maybe.isNull; // true

String

Validation: isEmail · isUrl · isPhoneNumber · isNumeric · isAlphabetic · isAlphanumeric · containsUppercase · containsLowercase · containsDigit · containsSpecialCharacter · isStrongPassword · isJson

Parsing: toIntSafe · toDoubleSafe · toBool · isNullOrEmpty (nullable) · isNullOrWhiteSpace

Case: capitalize · toTitleCase · toCamelCase · toPascalCase · toSnakeCase · toKebabCase

Slicing: truncate · reverse · removeWhitespace · collapseWhitespace · before · after · between · replaceLast · countOccurrences · initials · masked · onlyDigits · withoutDigits · slugify

'john_smith'.toCamelCase();      // johnSmith
'John Smith'.initials();         // JS
'hello'.masked();                // *ello

Number & Int

Formatting: toCurrency · toCompact · toPercentage · toDecimal · formatBytes

Predicates: isPositive · isZero · isDivisibleBy · percentageOf · isEven · isOdd (from dart:core)

Conversions: ordinal (int) · toBinary · toOctal · toHex (int) · milliseconds/seconds/minutes/hours/days → Duration · heightBox/widthBox → SizedBox · toRadians · toDegrees · isBetween

toPercentage treats the value as an already-scaled percentage (100 -> 100%), and toDecimal pads to exactly decimals fraction digits.

1.ordinal();              // 1st
5.toBinary();             // 101
1024.formatBytes();       // 1.00 KB
100.toPercentage();       // 100%
1.5.toDecimal(decimals: 3); // 1.500
10.heightBox;             // SizedBox(height: 10)
12.minutes;               // Duration(minutes: 12)

Double

toFixed(int fractionDigits) · lerp(other, t)

3.14159.toFixed(2);              // 3.14
10.0.lerp(20.0, 0.5);            // 15.0

DateTime

Checks: isToday · isYesterday · isTomorrow · isSameDay · isSameMonth · isSameYear · isBetween · isWeekend · isWeekday · isLeapYear · isInFuture · isInPast

Boundaries: startOfDay/endOfDay · startOfWeek/endOfWeek · startOfMonth/endOfMonth · startOfYear/endOfYear · tomorrow · yesterday

Helpers: copyWith · ageInYears · quarter Formatting: format · formattedDate · timeAgo

final now = DateTime.now();
now.startOfMonth;          // 1st of the month
now.ageInYears();          // whole years
now.timeAgo(context);      // "5 minutes ago"

Duration

inWeeks · format()

const Duration(hours: 2, minutes: 3, seconds: 45).format(); // 2:03:45

Iterable

Selection: firstWhereOrNull · distinctBy · countWhere · containsAll · containsAny

Nullable: isNullOrEmpty (on Iterable<T>?) · whereNotNull (on Iterable<T?>, narrows to List<T>)

Math (Iterable<num>): sum · min · max · average; plus sumBy · averageBy

Grouping/joining: groupBy · insertBetween · zip · unzip · flatten

List

takeLast · takeFirst · chunked · reversedList · rotate · distinct · shuffledList · mapToList · safeGet · hasUniqueElements

[1, 2, 3, 4, 5].rotate(2);   // [4, 5, 1, 2, 3]
[1, 2, 3].chunked(2);        // [[1, 2], [3]]

Map

getOrElse · getOrPut · deepMerge · merge · invert · where · filterKeys · filterValues · mapKeys · mapValues · pick · omit · keysOf

{'a': 1, 'b': 2}.invert();               // {1: a, 2: b}
{'a': 1, 'b': 2, 'c': 3}.pick(['a', 'c']); // {a: 1, c: 3}

Color

Conversion: toHex · colorFromHex(String) (top-level function)

Shading: darken · lighten · blend · inverse · complementary

Properties: hue · saturation · brightness · withBrightness · isDark · isLight · isTransparent · toMaterialColor

colorFromHex('#f00').lighten(0.2);
Colors.red.complementary;   // cyan
Colors.red.toMaterialColor();

BuildContext

Media: screenWidth · screenHeight · screenSize · viewInsets · viewPadding · safePadding · mediaQuery · devicePixelRatio · textScaler · orientation · isPortrait · isLandscape · hideKeyboard

Device/Theme: isMobile · isTablet · isDesktop · theme · textTheme · colorScheme · primaryColor · accentColor · scaffoldBackgroundColor · iconTheme · locale · textDirection

if (context.isTablet) { /* ... */ }
context.hideKeyboard();

Widget

Layout: padding · margin · background · border · center · expanded · flexible · align · size · width · height · constrained · aspectRatio

Interaction: onTap · onLongPress · onDoubleTap · inkWell · tooltip

Effect: opacity · visible · safeArea · circular · elevated · blur · rotated · scaled

Text('Hello').padding().background(Colors.red).tooltip('hi');
Text('Tap').inkWell(onTap);

TextStyle

size · scaleSize · weight · bold · semiBold · light · medium · color · letterSpacing · wordSpacing · italic · lineHeight · backgroundColor · underline · lineThrough · overline · noDecoration · decorationThickness · mergeWith · fontFamily · withShadow · withShadows · glow · responsiveSize · outlined

TextStyle().bold.color(Colors.red).size(24);

Icon

withColor(Color) · withSize(double)

Image

toBase64() · withFilter(ColorFilter)

File

sizeBytes · sizeFormatted · sizeInMB · isImage · isVideo · isAudio · readAsStringSafe

Only available where dart:io exists (not on the web).

File('photo.jpg').isImage;   // true
file.sizeFormatted();        // "1.23 MB"

EdgeInsets

copyWith({left, top, right, bottom}) — Flutter's EdgeInsets has none.

State

safeSetState(fn) — calls setState only while the widget is mounted.

Platform

On BuildContext: platform and targetPlatform expose isAndroid, isIOS, isWeb, isMacOS, isWindows, isLinux, isFuchsia.

Navigation

Transitions: navigateTo · navigateBack · navigateToReplace · navigateAndRestore (runs onBack on pop) · navigateAndRemoveUntil · pushScreen · pushWithFade · pushWithSlide · replaceScreen

Stack: clearStackAndShow · popUntilRoute · popToFirst · canPop · maybePop · popWithResult · currentRouteName

Presenters: showSheet · showAppDialog

context.pushWithSlide(DetailsScreen());
context.canPop;
context.showSheet(child);

Alert & Snackbar

showCusDialog(Widget) · showSnackBar(String) · removeSnackBar()

Form Validators

Composable String? Function(String?) validators, ready for TextFormField:

requiredField · emailValidator · phoneValidator · minLengthValidator · maxLengthValidator

TextFormField(validator: emailValidator);

---

Examples

A few pending UI recipes:

// Ripple button with padding and tooltip
Text('Submit').inkWell(() => submit()).padding(EdgeInsets.all(12));

// Slide-in navigation to a screen
context.pushWithSlide(const ProfileScreen());

// Form field with validation
TextFormField(
  controller: _email,
  validator: emailValidator,
  decoration: const InputDecoration(labelText: 'Email'),
);

---

Contributing

Contributions are welcome — see CONTRIBUTING.md. To keep the package consistent:

1. Extensions follow the Dart style guide and flutter_lints.
2. New extensions should be added under lib/extensions/ with a focused file per type, then exported from lib/extensions.dart.
3. Add tests in test/ — run flutter test and flutter analyze before submitting.
4. Update this README and the CHANGELOG.md for user-visible changes.

---

License

MIT

Copyright © Extensions Core contributors.