String Utilities

String Utilities is a Dart package that provides a collection of useful extension methods for working with strings in Dart and Flutter. The package includes functions for trimming, capitalizing, reversing, retrieving words, and many more.

⭐️ If you find this package useful, please consider giving it a star on GitHub – it helps others to discover it!

Features

ifEmpty: Returns a default value if a string is empty.
isBlank: Checks if a string is blank (empty or contains only whitespace).
toCapitalize: Capitalizes the first letter of a string.
toReverse: Reverses the characters in a string.
toLowerCase: Converts a string to lowercase.
toCapitalizeEachWord: Capitalizes the first letter of each word in a string.
removeLastWord: Removes the last word from a string.
getLastWord: Retrieves the last word from a string.
isEquals: Compares two strings with optional case-insensitive comparison and trimming.
isPhoneNumber: Validates if the string is a valid phone number format.
isUrl: Checks if a string is a valid URL.
isNumeric: Checks if a string contains only numbers (integer or decimal).
isAlphanumeric: Checks if a string contains only letters and numbers.
onlyNumbers: Extracts only the digit characters from a string.
onlyLetters: Extracts only alphabetic characters from a string.
truncate: Truncates a string to a maximum length and adds ellipsis.
removeAllWhitespace: Removes all whitespace characters from a string.
toSnakeCase: Converts a string to snake_case format.
toCamelCase: Converts a string to camelCase format.
repeat: Repeats the string a specified number of times.
mask: Replaces part of the string with a masking character.
isPalindrome: Checks if the string is a palindrome, ignoring case and non-alphanumeric characters.
safeReverse: Reverses a string safely (grapheme/emoji aware).
chunked: Splits a string into chunks of a given size.
take: Returns the first n characters of a string.
drop: Removes the first n characters from a string.
padStartCustom: Pads the start of the string with a custom pattern until a given width.
padEndCustom: Pads the end of the string with a custom pattern until a given width.
splitByLength: Splits a string into fixed-length segments (alias of chunked).
toSentenceCase: Converts the string to sentence case (first letter uppercase).
containsOnly: Checks if the string contains only allowed characters.
removeSpecialCharacters: Removes all non-alphanumeric characters (except space).
toBase64: Encodes the string to Base64.
fromBase64: Decodes a Base64 string back to a normal string

Getting Started

To use this package in your Flutter or Dart project, add the following dependency to your pubspec.yaml file:

dependencies:
  string_utility: ^1.2.0

✅ Tests

All unit tests are written using the test package.

✔️ All tests are passing

Usage

ifEmpty Example

The ifEmpty method returns a default value if the string is empty; otherwise, it returns the original string.

String name = "John Doe".ifEmpty("Unknown");

print(name); // Output: "John"

isBlank Example

The isBlank method returning true if it is empty or contains only whitespace, and false otherwise.

bool isBlank = "   ".isBlank(); // true
bool isNotBlank = "Text".isBlank(); // false

toCapitalize Example

The toCapitalize method check if the string is empty, it returns the original string.Otherwise, it converts the first character to uppercase and appends the rest of the string.

String capitalized = "hello".toCapitalize(); // "Hello"

toReverse Example

The toReverse method splits the string into individual characters, reverses the order, and joins them back into a single string.

String reversed = "Flutter".toReverse(); // "rettulF"

toLowerCase Example

The toLowerCase method return all converted characters in the string to lowercase.

String lowerCase = "HELLO WORLD".toLowerCase(); // "hello world"

toCapitalizeEachWord Example

The toCapitalizeEachWord method splits the string by spaces and capitalizes the first letter of each word.

String capitalizedWords = "make each word capitalized"
    .toCapitalizeEachWord(); // "Make Each Word Capitalized"

removeLastWord Example

The removeLastWord method splits the string by whitespace, removes the last word, and then joins the remaining words into a new string.If the string has only one word or is empty, then result is an empty string.

String result = "This is a sentence.".removeLastWord();

print(result); // Output: "This is a"

getLastWord Example

The getLastWord method splits the string by whitespace and retrieves the last word.If the string is empty or has no words, it returns an empty string.

String lastWord = "This is a sentence.".getLastWord();

print(lastWord); // Output: "sentence."

isEquals Example

The isEquals method returns true if the current string is equivalent to other based on the given flags.

bool caseInsensitiveEqual = "hello".isEquals("HELLO", ignoreCase: true); // true
bool trimmedEqual = " hello ".isEquals("hello", trim: true); // true
bool caseSensitiveEqual = "hello".isEquals("HELLO"); // false
bool bothEqual = " hello ".isEquals("HELLO", ignoreCase: true, trim: true); // true

isEmail Example

The isEmail method checks if the string is in a valid email format using a regular expression.

"user@example.com".isEmail(); // true
"invalid@com".isEmail(); // false

isPhoneNumber Example

The isPhoneNumber method checks if the string is a valid international phone number, with optional + prefix and 10–15 digits.

"+919876543210".isPhoneNumber(); // true
"12345".isPhoneNumber(); // false

isUrl Example

The isUrl method verifies whether the string is a valid URL with http, https, or ftp schemes.

"https://flutter.dev".isUrl(); // true
"not_url".isUrl(); // false

isNumeric Example

The isNumeric method checks if the string represents a valid number (integer or decimal).

"123".isNumeric(); // true
"123.45".isNumeric(); // true
"abc".isNumeric(); // false

isAlphanumeric Example

The isAlphanumeric method checks if the string contains only letters and numbers.

"abc123".isAlphanumeric(); // true
"abc 123!".isAlphanumeric(); // false

onlyNumbers Example

The onlyNumbers method removes all non-numeric characters from the string and returns only the digits.

"(123)-456-7890".onlyNumbers(); // "1234567890"

onlyLetters Example

The onlyLetters method removes all non-letter characters and returns only alphabetic characters.

"abc123!".onlyLetters(); // "abc"

truncate Example

The truncate method shortens the string to the given length and appends an optional ellipsis.

"Hello World!".truncate(5); // "Hello..."

removeAllWhitespace Example

The removeAllWhitespace method removes all whitespace characters from the string.

" Hello \n World ".removeAllWhitespace(); // "HelloWorld"

toSnakeCase Example

The toSnakeCase method converts camelCase or PascalCase strings into snake_case format.

"helloWorld".toSnakeCase(); // "hello_world"
"MyHTTPResponse".toSnakeCase(); // "my_http_response"

toCamelCase Example

The toCamelCase method converts a snake_case or kebab-case string to camelCase.

"hello_world".toCamelCase(); // "helloWorld"
"my-awesome-text".toCamelCase(); // "myAwesomeText"

repeat Example

The repeat method repeats the string a given number of times and returns the concatenated result.

"ha".repeat(3); // "hahaha"

mask Example

The mask method replaces a portion of the string (from start to end) with the provided mask character.

"1234567890".mask(start: 2, end: 6); // "12****7890"
"abcdef".mask(maskChar: "#"); // "######"
"Short".mask(start: 3); // "Sho*"

isPalindrome Example

The isPalindrome getter checks if the string reads the same forward and backward, ignoring case and non-alphanumeric characters.

"A man, a plan, a canal: Panama".isPalindrome; // true
"racecar".isPalindrome; // true
"hello".isPalindrome; // false

safeReverse Example

The safeReverse method reverses a string while preserving grapheme clusters (e.g., emojis, accented characters).

"hello".safeReverse(); // "olleh"
"👨‍👩‍👧‍👦".safeReverse(); // "👨‍👩‍👧‍👦" (grapheme-safe)

chunked Example

The chunked method splits the string into chunks of the given size.

"abcdef".chunked(2); // ["ab", "cd", "ef"]
"hello".chunked(3); // ["hel", "lo"]

take Example

The take method returns the first count characters from the string.

"hello".take(2); // "he"
"flutter".take(10); // "flutter" (clamped to length)

drop Example

The drop method returns the string after removing the first count characters.

"hello".drop(2); // "llo"
"flutter".drop(10); // "" (clamped)

padStartCustom Example

The padStartCustom method add pads to the beginning of the string to reach a specified width using the provided padding character/string.

"42".padStartCustom(5, "0"); // "00042"
"hello".padStartCustom(10, "-"); // "-----hello"

padEndCustom Example

The padEndCustom method add pads to the end of the string to reach a specified width using the provided padding character/string.

"42".padEndCustom(5, "0"); // "42000"
"hi".padEndCustom(6, "*"); // "hi****"

splitByLength Example

The splitByLength method add the string into substrings of the specified length. It is an alias of chunked.

"1234567890".splitByLength(3); // ["123", "456", "789", "0"]

toSentenceCase Example

The toSentenceCase method converts a string to sentence case (first letter uppercase, rest lowercase).

"hello WORLD".toSentenceCase(); // "Hello world"
"FLUTTER".toSentenceCase(); // "Flutter"

containsOnly Example

The containsOnly method checks if a string contains only characters from the allowed set.

"12345".containsOnly("0123456789"); // true
"abc123".containsOnly("abc"); // false

removeSpecialCharacters Example

The removeSpecialCharacters method removes all non-alphanumeric characters (excluding spaces).

"Hello, World! 123.".removeSpecialCharacters(); // "Hello World 123"
"@#\$%^".removeSpecialCharacters(); // ""

toBase64 Example

The toBase64 method encodes the string into a Base64 string.

"hello".toBase64(); // "aGVsbG8="

fromBase64 Example

Then fromBase64 method decodes a Base64 string back to a regular string.

"aGVsbG8=".fromBase64(); // "hello"

🤝 Contributing

Contributions are welcome and greatly appreciated!

If you have suggestions for improvements, bug fixes, or new features, feel free to:

Fork the repository
Create a new branch:
```
git checkout -b feature/my-feature
```
```
git commit -m 'Added my feature'
```
```
git push origin feature/my-feature
```
Please make sure your code follows the Dart/Flutter style guide, is well-documented, and tested.

If you're not ready to submit code, you can still help by:

Reporting bugs or issues
Requesting new features
Improving documentation

Thank you for helping improve this project! 🙌

💡 Tip:

This format ensures compatibility with both GitHub and pub.dev README previews. Let me know if you want to include a CONTRIBUTING.md link or a code of conduct reference too.

🙌 Credits

This package was created and is maintained by Pratik Amonkar.
Contributions are welcome — see CONTRIBUTING.md for details.

If you use this package in your project, feel free to credit the author or link back to the pub.dev page.
A simple mention helps support open source!