> For the complete documentation index, see [llms.txt](https://strings.onepub.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://strings.onepub.dev/overview.md).
# Overview
The Strings package is an evolution of work originally produced by Andrew Mezoni.
The purpose of the Strings package is to provide:
* Complement Dart's core `String` class with common string utilities.
* Add extension methods to non-null strings where useful.
* Provide static methods for values that may be null.
* Wrap many core `String` methods for nullable input.
A core objective is to handle null input predictably. Some methods still throw for invalid indexes or missing delimiters; their pages describe those cases.
```dart
import 'package:strings/strings.dart';
// pass a short string and we can pad it (or not).
Strings.right('one', 4, pad: Pad.left);
// ' one'
// passing null works too.
Strings.right(null, 4, pad: Pad.left);
// ' '
```
## Sponsored by OnePub
Strings is sponsored by [OnePub](https://onepub.dev/), the private Dart repository service.
OnePub lets you privately share Dart packages with your team and customers.
Try it for free and publish your first private package in seconds.
|  | Publish a private package in five commands:
flutter pub global activate onepub
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| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
## Namespace
The package groups nullable utility methods as statics on `Strings` rather than as global functions.
This makes them easy to find with IDE completion: type `Strings.` to see the available methods.
Use `Strings.methodName(...)` for nullable values:
```dart
Strings.right(null, 4, pad: Pad.left); // ' '
Strings.isBlank(null); // true
```
## Nullable strings
Most Dart strings are non-null, but some values have type `String?`. `Strings` methods let you work with those values directly.
If you need to trim a `String?`, you can use the nullable wrapper:
```dart
String? value = null;
Strings.trim(value); // ''
```
For a non-null `String`, use its existing method or one of this package's extensions:
```dart
' Dart '.trim(); // 'Dart'
'hello world'.toProperCase(); // 'Hello World'
```
## Utility methods
The manual follows the existing groups:
* [Blank](/blank.md) checks whitespace and provides fallbacks.
* [Empty](/empty.md) checks zero-length strings and handles null values.
* [Parts](/parts.md) takes, pads, joins, masks, counts and extracts text.
* [Safe](/safe.md) wraps core `String` methods for nullable input.
* [Style](/style.md) checks or changes letter case and whitespace.
* [Transform](/transform.md) reverses, escapes and normalizes text.
* [Type](/type.md) checks numeric and ASCII content and compares values.
Common calls include:
```dart
Strings.orElseOnBlank(' ', 'Guest'); // 'Guest'
Strings.join(['red', 'green'], separator: ', '); // 'red, green'
Strings.toSnakeCase('camelCase'); // 'camel_case'
```
## Extensions to String
The `StringEx` extension adds methods to non-null `String` values. The corresponding `Strings` statics accept nullable input when their signatures use `String?`:
```dart
import 'package:strings/strings.dart';
'hello world'.toProperCase(); // 'Hello World'
Strings.toProperCase(null); // ''
'one'.right(4, pad: Pad.left); // ' one'
Strings.right(null, 4, pad: Pad.left); // ' '
' '.isBlank(); // true
Strings.isBlank(null); // true
```
### Available extensions
`StringEx` adds these methods to non-null strings. Each has a corresponding `Strings` static method that accepts a nullable receiver.
* **Blank and type checks:** `isBlank`, `isNotBlank`, `isLowerCase`, `isUpperCase`, `isNumeric`, `isAscii`, `startsWithLowerCase`, `startsWithUpperCase`, `equalsIgnoreCase`.
* **Parts:** `abbreviate`, `countMatches`, `left`, `right`, `removePrefix`, `removeSuffix`, `partition`, `lastPartition`, `substringAfter`, `substringAfterLast`, `substringBeforeLast`.
* **Style and transform:** `toCamelCase`, `toCapitalised`, `toProperCase`, `toSnakeCase`, `reverse`, `normalizeSpace`, `replaceLineEndings`, `toEscaped`, `toPrintable`.
## Complete method index
These are the public static methods on `Strings`. Follow each group link for signatures, examples and edge cases. `Pad.left`, `Pad.right` and `Pad.none` are described under [Pad](/parts.md#pad).
### [Blank](/blank.md)
`isBlank`, `isNotBlank`, `orElseOnBlank`.
### [Empty](/empty.md)
`isEmpty`, `isNotEmpty`, `orElse`, `orElseCall`, `toEmpty`.
### [Parts](/parts.md)
`abbreviate`, `countMatches`, `hidePart`, `join`, `lastPartition`, `left`, `partition`, `removePrefix`, `removeSuffix`, `right`, `substringAfter`, `substringAfterLast`, `substringBeforeLast`, `upTo`, `within`.
### [Safe](/safe.md)
`allMatches`, `codeUnitAt`, `codeUnits`, `compareTo`, `contains`, `endsWith`, `indexOf`, `lastIndexOf`, `length`, `matchAsPrefix`, `padLeft`, `padRight`, `replaceAll`, `replaceAllMapped`, `replaceFirst`, `replaceFirstMapped`, `replaceRange`, `runes`, `split`, `splitMapJoin`, `startsWith`, `substring`, `toLowerCase`, `toUpperCase`, `trim`, `trimLeft`, `trimRight`.
### [Style](/style.md)
`isLowerCase`, `isPrintable`, `isUpperCase`, `isWhitespace`, `isWhitespaceRune`, `startsWithLowerCase`, `startsWithUpperCase`, `toCamelCase`, `toCapitalised`, `toLowerCase`, `toProperCase`, `toSnakeCase`, `toUpperCase`.
### [Transform](/transform.md)
`conjuctionJoin`, `normalizeSpace`, `replaceLineEndings`, `reverse`, `toEscaped`, `toPrintable`, `toUnicode`.
### [Type](/type.md)
`equals`, `equalsIgnoreCase`, `isAscii`, `isDigits`, `isNumeric`.
`toLowerCase` and `toUpperCase` appear under both [Safe](/safe.md) and [Style](/style.md), because they are nullable wrappers for core `String` methods and common case conversions.
## Contributing
Contributions are welcome in the [Strings GitHub repository](https://github.com/onepub-dev/strings). Follow the existing code layout when adding a method.
### Unit Tests
Include focused unit tests for each new function.