Dart Extension Methods

This repository contains a set of useful extension methods for common types in Flutter Dart. These extensions enhance the functionality of standard classes, providing convenient methods for everyday tasks.

Table of Contents

Introduction

Dart extensions are a powerful feature that allows you to add methods to existing classes without modifying the original class. This repository provides a collection of useful extensions for common Dart types such as String, num, List, Map, and DateTime. These extensions make it easier to perform common tasks, improve code readability, and reduce boilerplate code.

Boolean Extensions

Summarizing the BooleanExtensions functionality:

Method Description Example Usage Output
toggle() Toggles the boolean value. true.toggle() false
toInt() Converts the boolean to an integer (1 for true, 0 for false). true.toInt() 1
toStringValue() Converts the boolean to a string ('true' or 'false'). false.toStringValue() 'false'
toYesNoString() Returns 'Yes' for true and 'No' for false. true.toYesNoString() 'Yes'
toOnOffString() Returns 'On' for true and 'Off' for false. false.toOnOffString() 'Off'
toEnableDisableString() Returns 'Enable' for true and 'Disable' for false. true.toEnableDisableString() 'Enable'
toActiveInactiveString() Returns 'Active' for true and 'Inactive' for false. false.toActiveInactiveString() 'Inactive'
toCheckmarkString() Returns '✓' for true and '✗' for false. true.toCheckmarkString() '✓'
toCustomString() Converts to custom string values for true and false. true.toCustomString(trueValue: 'Start', falseValue: 'Stop') 'Start'
toCustomInt() Returns custom integer values for true and false. false.toCustomInt(trueValue: 5, falseValue: -5) -5
toggleDelayed() Toggles the boolean value after a delay. await true.toggleDelayed(Duration(seconds: 1)) false (after 1s)
toBinaryString() Converts the boolean to a binary string ("1" or "0"). false.toBinaryString() "0"
toSuccessFailureString() Returns 'Success' for true and 'Failure' for false. true.toSuccessFailureString() 'Success'
toAllowedDeniedString() Returns 'Allowed' for true and 'Denied' for false. false.toAllowedDeniedString() 'Denied'
toPassFailString() Returns 'Passed' for true and 'Failed' for false. true.toPassFailString() 'Passed'

Case Extensions

Summarizing the CaseExtensions functionality:

Method Description Example Usage Output
toLowerCase() Converts the string to lowercase. 'Hello World'.toLowerCase() 'hello world'
toUpperCase() Converts the string to uppercase. 'Hello World'.toUpperCase() 'HELLO WORLD'
toKebabCase Converts the string to kebab case (lowercase with hyphens). 'Hello World'.toKebabCase 'hello-world'
toSnakeCase Converts the string to snake case (lowercase with underscores). 'Hello World'.toSnakeCase 'hello_world'
toCamelCase Converts the string to camel case. 'hello world'.toCamelCase 'helloWorld'
toPascalCase() Converts the string to pascal case. 'hello world'.toPascalCase() 'HelloWorld'
toTitleCase() Capitalizes the first letter of each word. 'hello world'.toTitleCase() 'Hello World'
toSentenceCase() Capitalizes the first letter of the sentence. 'hello world'.toSentenceCase() 'Hello world'
toDotCase() Converts the string to dot case (lowercase with dots). 'Hello World'.toDotCase() 'hello.world'
toConstantCase() Converts the string to constant case (uppercase with underscores). 'Hello World'.toConstantCase() 'HELLO_WORLD'
toPathCase() Converts the string to path case (lowercase with slashes). 'Hello World'.toPathCase() 'hello/world'
toAlternatingCase() Alternates the case of each character. 'hello world'.toAlternatingCase() 'hElLo WoRlD'
normalizeCase() Cleans and normalizes case, removing extra spaces and special characters. ' Hello @World! '.normalizeCase() 'Hello World'
toHeaderCase() Capitalizes words and joins them with hyphens. 'hello world'.toHeaderCase() 'Hello-World'
toProperCase() Capitalizes first letters of words except articles (e.g., a, the). 'a quick brown fox jumps over the lazy dog'.toProperCase() 'A Quick Brown Fox Jumps over the Lazy Dog'
normalizeSpaces() Reduces multiple spaces to a single space. ' Hello World '.normalizeSpaces() 'Hello World'

DateTime Extensions

Summarizing the DateTimeExtensions functionality:

Method Description Example Usage Output
isToday Checks if the date is today. DateTime.now().isToday true
isYesterday Checks if the date is yesterday. DateTime.now().subtract(Duration(days: 1)).isYesterday true
isTomorrow Checks if the date is tomorrow. DateTime.now().add(Duration(days: 1)).isTomorrow true
isThisWeek Checks if the date is in the current week. DateTime.now().isThisWeek true
isThisMonth Checks if the date is in the current month. DateTime.now().isThisMonth true
isThisYear Checks if the date is in the current year. DateTime.now().isThisYear true
shortDateString Formats the date as MM/dd/yyyy. DateTime.now().shortDateString 1/19/2025
longDateString Formats the date as MMMM dd, yyyy. DateTime.now().longDateString January 19, 2025
twelveHourTimeString Formats the time as hh:mm a. DateTime.now().twelveHourTimeString 9:45 AM
twentyFourHourTimeString Formats the time as HH:mm. DateTime.now().twentyFourHourTimeString 09:45
startOfDay Gets the start of the day (00:00:00). DateTime.now().startOfDay 2025-01-19 00:00:00.000
endOfDay Gets the end of the day (23:59:59). DateTime.now().endOfDay 2025-01-19 23:59:59.000
startOfWeek Gets the start of the week (Sunday). DateTime.now().startOfWeek 2025-01-12 00:00:00.000
endOfWeek Gets the end of the week (Saturday). DateTime.now().endOfWeek 2025-01-18 23:59:59.000
startOfMonth Gets the start of the month. DateTime.now().startOfMonth 2025-01-01 00:00:00.000
endOfMonth Gets the end of the month. DateTime.now().endOfMonth 2025-01-31 23:59:59.000
startOfYear Gets the start of the year. DateTime.now().startOfYear 2025-01-01 00:00:00.000
endOfYear Gets the end of the year. DateTime.now().endOfYear 2025-12-31 23:59:59.000
addDays(days) Adds a specified number of days to the date. DateTime.now().addDays(5) 2025-01-24
subtractDays(days) Subtracts a specified number of days from the date. DateTime.now().subtractDays(5) 2025-01-14
addMonths(months) Adds a specified number of months to the date. DateTime.now().addMonths(2) 2025-03-19
subtractMonths(months) Subtracts a specified number of months from the date. DateTime.now().subtractMonths(2) 2024-11-19
addYears(years) Adds a specified number of years to the date. DateTime.now().addYears(1) 2026-01-19
subtractYears(years) Subtracts a specified number of years from the date. DateTime.now().subtractYears(1) 2024-01-19
differenceInDays(other) Gets the difference in days between two dates. DateTime.now().differenceInDays(DateTime(2025, 1, 1)) 18
isWeekend(type) Checks if the date falls on a weekend. DateTime.now().isWeekend(FormatBy.EN) true (if Saturday or Sunday)
isLeapYear Checks if the year is a leap year. DateTime(2024, 1, 1).isLeapYear true
weekNumber Gets the week number of the year. DateTime.now().weekNumber 3 (for third week of the year)
relativeTime Gets the relative time string (e.g., "2 hours ago"). DateTime.now().subtract(Duration(days: 2)).relativeTime 2 days ago
getAge Calculates the age from a birthdate. DateTime(2000, 1, 1).getAge 25 (in 2025)
daysInMonth Gets the number of days in the current month. DateTime(2025, 2, 1).daysInMonth 28
remainingDaysInMonth Gets the remaining days in the current month. DateTime(2025, 1, 19).remainingDaysInMonth 12

Flag Extensions

This ConvertFlag extension provides a range of utilities for converting, validating, and handling country codes and flag emojis. Below is a summary of the key features:

Method/Property Description Example Usage Output
toFlag Converts a 2-letter country code to a flag emoji. 'US'.toFlag 🇺🇸
isValidCountryCode Checks if the string is a valid 2-letter country code. 'US'.isValidCountryCode true
toFlagSafe(fallback) Converts a 2-letter country code to a flag emoji with a fallback for invalid codes. 'XX'.toFlagSafe('N/A') N/A
fromFlag Converts a flag emoji back to its corresponding 2-letter country code. '🇺🇸'.fromFlag US
isFlag Checks if the string is a valid flag emoji. '🇺🇸'.isFlag true
flagCodePoints Returns the Unicode code points of the flag emoji. 'US'.flagCodePoints [127482, 127480]
toMultiFlags Converts a comma-separated list of country codes to flag emojis. 'US, CA, GB'.toMultiFlags 🇺🇸 🇨🇦 🇬🇧
isRegionFlag Checks if the string is a valid region flag emoji. '🇺🇸'.isRegionFlag true
toFlagUnicode Returns the Unicode escape sequence for the flag emoji. 'US'.toFlagUnicode \u{1f1fa}\u{1f1f8}
toHtmlFlag Converts the country code to an HTML-compatible flag representation. 'US'.toHtmlFlag 🇺🇸
normalizeCountryCode Validates and normalizes a country code to uppercase. 'us'.normalizeCountryCode US
isISOCountryCode Checks if the country code exists in the ISO 3166-1 alpha-2 standard. 'US'.isISOCountryCode true

Key Notes

This extension is particularly useful for applications dealing with country codes, flags, and internationalization.

Iterable Extensions

This IndexedIterable extension provides additional utility methods for working with Iterable collections by incorporating indices into the operations. Below is a summary of its features:

Method Description Example Usage Output
mapIndexed Maps each element of the iterable to a new value using its index and item. [1, 2, 3].mapIndexed((index, item) => '$index:$item') ['0:1', '1:2', '2:3']
groupByIndexed Groups elements into a map based on a key selector function that takes both the index and the item. [10, 20, 30, 40].groupByIndexed((index, item) => index % 2) {0: [10, 30], 1: [20, 40]}
elementAtOrDefault Retrieves the element at the specified index or returns a default value if the index is out of bounds. [1, 2, 3].elementAtOrDefault(5, -1) -1
windowIndexed Creates sliding windows of a specified size over the elements of the iterable. [1, 2, 3, 4].windowIndexed(2) [[1, 2], [2, 3], [3, 4]]

List Extensions

Summarizing the ListExtensions functionality:

Method Description Example Usage Output
isNullOrEmpty Checks if the list is null or empty. [1, 2, 3].isNullOrEmpty false
isNotNullOrEmpty Checks if the list is not null or empty. [1, 2, 3].isNotNullOrEmpty true
containsElement Checks if the list contains a specific element. [1, 2, 3].containsElement(2) true
firstOrDefault Gets the first element or a default value if empty. [].firstOrDefault(0) 0
lastOrDefault Gets the last element or a default value if empty. [].lastOrDefault(0) 0
whereCondition Filters the list based on a condition. [1, 2, 3].whereCondition((e) => e > 1) [2, 3]
mapTo Maps each element to a new value. [1, 2, 3].mapTo((e) => e * 2) [2, 4, 6]
toSet Converts the list to a set. [1, 1, 2, 3].toSet() {1, 2, 3}
sortBy Sorts the list in ascending order. [3, 1, 2].sortBy((e) => e) [1, 2, 3]
sortByDescending Sorts the list in descending order. [3, 1, 2].sortByDescending((e) => e) [3, 2, 1]
shuffled Shuffles the elements in the list. [1, 2, 3].shuffled Example: [3, 1, 2]
all Checks if all elements satisfy a condition. [1, 2, 3].all((e) => e > 0) true
any Checks if any element satisfies a condition. [1, 2, 3].any((e) => e > 2) true
indexOfElement Gets the index of the first occurrence of an element. [1, 2, 3].indexOfElement(2) 1
lastIndexOfElement Gets the index of the last occurrence of an element. [1, 2, 3, 2].lastIndexOfElement(2) 3
removeFirstOccurrence Removes the first occurrence of an element. [1, 2, 3, 2].removeFirstOccurrence(2) [1, 3, 2]
removeAllOccurrences Removes all occurrences of an element. [1, 2, 3, 2].removeAllOccurrences(2) [1, 3]
distinct Gets the distinct elements in the list. [1, 2, 2, 3].distinct [1, 2, 3]
firstN Gets the first N elements of the list. [1, 2, 3].firstN(2) [1, 2]
lastN Gets the last N elements of the list. [1, 2, 3].lastN(2) [2, 3]
chunk Splits the list into chunks of a specified size. [1, 2, 3, 4].chunk(2) [[1, 2], [3, 4]]
isPalindrome Checks if the list is a palindrome. [1, 2, 1].isPalindrome true
insertAt Inserts an element at a specific index. [1, 3].insertAt(1, 2) [1, 2, 3]
removeAt Removes the element at a specific index. [1, 2, 3].removeAt(1) [1, 3]
replaceAll Replaces all occurrences of an element with another. [1, 2, 2, 3].replaceAll(2, 4) [1, 4, 4, 3]
rotateRight Rotates the list to the right by a number of positions. [1, 2, 3].rotateRight(1) [3, 1, 2]
rotateLeft Rotates the list to the left by a number of positions. [1, 2, 3].rotateLeft(1) [2, 3, 1]
takeWhileCondition Takes elements from the start while a condition is satisfied. [1, 2, 3].takeWhileCondition((e) => e < 3) [1, 2]
skipWhileCondition Skips elements from the start while a condition is satisfied. [1, 2, 3].skipWhileCondition((e) => e < 3) [3]
groupBy Groups elements by a key. [1, 2, 3, 4].groupBy((e) => e % 2 == 0 ? 'Even' : 'Odd') {'Odd': [1, 3], 'Even': [2, 4]}
partition Partitions the list into two lists based on a condition. [1, 2, 3, 4].partition((e) => e % 2 == 0) ([2, 4], [1, 3])
duplicates Finds duplicate elements in the list. [1, 2, 2, 3].duplicates [2]
splitWhen Splits the list when a condition is met. [1, 2, 3, 4].splitWhen((e) => e == 3) [[1, 2], [3, 4]]

Map Extensions

Summarizing the MapExtensions functionality:

Method Description Example Usage Output
containsKey Checks if a key is present in the map. {1: 'one', 2: 'two'}.containsKey(2) true
containsValue Checks if a value is present in the map. {1: 'one', 2: 'two'}.containsValue('three') false
keysList Retrieves a list of keys in the map. {1: 'one', 2: 'two'}.keysList [1, 2]
valuesList Retrieves a list of values in the map. {1: 'one', 2: 'two'}.valuesList ['one', 'two']
removeWhere Removes entries from the map based on a condition. {1: 'one', 2: 'two'}.removeWhere((key, value) => value == 'two') {1: 'one'}
filter Filters entries based on a condition. {1: 'one', 2: 'two'}.filter((key, value) => key > 1) {2: 'two'}
merge Merges two maps. {1: 'one'}.merge({2: 'two'}) {1: 'one', 2: 'two'}
firstKey Gets the first key matching a condition. {1: 'one', 2: 'two'}.firstKey((key, value) => value == 'two') 2
firstValue Gets the first value matching a condition. {1: 'one', 2: 'two'}.firstValue((key, value) => key == 2) 'two'
toJsonString Converts the map to a JSON string. {1: 'one', 2: 'two'}.toJsonString() '{"1":"one","2":"two"}'
addIfAbsent Adds a new entry if the key does not exist in the map. {1: 'one'}.addIfAbsent(2, 'two') {1: 'one', 2: 'two'}
updateValue Updates the value for a given key if the key exists. {1: 'one', 2: 'two'}.updateValue(2, 'updated') {1: 'one', 2: 'updated'}

Num Extensions

Summarizing the NumExtensions functionality:

Method Description Example Usage Output
toPercentageString Converts the number to a percentage string. 0.25.toPercentageString() '25.00%'
isEvenNumber Checks if the number is even. 4.isEvenNumber true
isOddNumber Checks if the number is odd. 3.isOddNumber true
clamp Clamps the number within a specified range. 5.clamp(1, 10) 5
roundToDecimalPlaces Rounds the number to a specified number of decimal places. 3.14159.roundToDecimalPlaces(2) 3.14
isCloseTo Checks if the number is within a specified tolerance of another number. 5.isCloseTo(5.0000001) true
toRadians Converts degrees to radians. 180.toRadians 3.141592653589793
toDegrees Converts radians to degrees. 3.141592653589793.toDegrees 180.0
limitToMax Limits the number to a maximum value. 12.limitToMax(10) 10
limitToMin Limits the number to a minimum value. 5.limitToMin(10) 10
toCurrencyString Converts the number to a currency formatted string. 1234.56.toCurrencyString() '$1,234.56'
isPrime Checks if the number is a prime number. 7.isPrime true
factors Generates a list of factors for the number. 28.factors [1, 2, 4, 7, 14, 28]
isPerfectSquare Checks if the number is a perfect square. 16.isPerfectSquare true
isPositive Checks if the number is positive. 5.isPositive true
isNegative Checks if the number is negative. -5.isNegative true
toOrdinalString Converts the number to an ordinal string (e.g., 1st, 2nd). 3.toOrdinalString() '3rd'
toRomanNumeral Converts the number to a Roman numeral string. 1999.toRomanNumeral() 'MCMXCIX'
isInRange Checks if the number is within a specified range (inclusive). 5.isInRange(1, 10) true
absoluteValue Returns the absolute value of the number. Not provided in original Not provided in original

String Extensions

Summarizing the NumExtensions functionality:

Method Description Example Usage Output
capitalizeFirstLetter Capitalizes the first letter of the string. 'hello'.capitalizeFirstLetter() 'Hello'
isValidEmail Checks if the string is a valid email address. 'test@example.com'.isValidEmail() true
isValidUrl Checks if the string is a valid URL. 'https://example.com'.isValidUrl() true
trim Removes leading and trailing whitespaces. ' hello '.trim() 'hello'
isBlank Checks if the string is empty or consists only of whitespaces. ' '.isBlank true
isNotBlank Checks if the string is not empty and not consists only of whitespaces. 'hello'.isNotBlank true
replaceFirst Replaces the first occurrence of a substring. 'hello world'.replaceFirst('world', 'Dart') 'hello Dart'
replaceAll Replaces all occurrences of a substring. 'hello world'.replaceAll('l', 'x') 'hexxo worxd'
isNumeric Checks if the string contains only numeric characters. '12345'.isNumeric true
reverse Reverses the characters in the string. 'hello'.reverse() 'olleh'
isPalindrome Checks if the string is a palindrome. 'madam'.isPalindrome() true
limitLength Limits the length of the string to a specified number of characters. 'hello world'.limitLength(5) 'hello'
toCharList Converts the string to a list of characters. 'hello'.toCharList() ['h', 'e', 'l', 'l', 'o']
isAlphabetic Checks if the string contains only alphabetic characters. 'hello'.isAlphabetic() true
toDouble Converts the string to a double (if possible). '3.14'.toDouble() 3.14
toInt Converts the string to an integer (if possible). '123'.toInt() 123
isValidPhoneNumber Checks if the string is a valid phone number. '1234567890'.isValidPhoneNumber() true
extractNumbers Extracts numbers from the string. 'abc123def456'.extractNumbers() '123456'
replaceSpacesWithUnderscores Replaces spaces in the string with underscores. 'hello world'.replaceSpacesWithUnderscores() 'hello_world'
isEmail Checks if the string is a valid email address. 'test@example.com'.isEmail true
startsWith Checks if the string starts with a specific prefix. 'hello'.startsWith('he') true
endsWith Checks if the string ends with a specific suffix. 'hello'.endsWith('lo') true
replace Replaces a substring with another string. 'hello world'.replace('world', 'Dart') 'hello Dart'
firstNCharacters Gets the first N characters of the string. 'hello world'.firstNCharacters(5) 'hello'
lastNCharacters Gets the last N characters of the string. 'hello world'.lastNCharacters(5) 'world'
isWhitespace Checks if the string contains only whitespace characters. ' '.isWhitespace true
toTitleCase Converts the string to title case (capitalizing the first letter of each word). 'hello world'.toTitleCase() 'Hello World'
isUrl Checks if the string is a valid URL. 'https://example.com'.isUrl true
isJson Checks if the string is a valid JSON. '{"key": "value"}'.isJson true
repeat Repeats the string N times. 'hello'.repeat(3) 'hellohellohello'
isHexColor Checks if the string is a valid hexadecimal color code. '#ff5733'.isHexColor true
toBase64 Encodes the string to Base64. 'hello'.toBase64 'aGVsbG8='
fromBase64 Decodes the string from Base64. 'aGVsbG8='fromBase64 'hello'
indexOf Gets the index of the first occurrence of a substring. 'hello world'.indexOf('world') 6
isAlphanumeric Checks if the string contains only alphanumeric characters. 'hello123'.isAlphanumeric true
words Converts the string to a list of words. 'hello world'.words ['hello', 'world']
getNameInitial Returns the initials of the first and last name. 'John Doe'.getNameInitial() 'JD'

Feel free to use these extensions in your Flutter Dart projects to simplify and enhance your code!

🚀 Welcome Contributions! 🎉

Contributions are open! 💡 Feel free to contribute by:

  • 🆕 Adding more extensions
  • ✨ Improving existing ones
  • 🐞 Fixing bugs
  • 💭 Suggesting new features

Let’s build a comprehensive collection of Dart extensions together! 🤝 Your help is highly appreciated! 🙏

Libraries

extension_service
helpers/currency_helper
helpers/enums