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https://github.com/simc/dartx

Superpowers for Dart. Collection of useful static extension methods.
https://github.com/simc/dartx

dart flutter hacktoberfest static-extension superpowers

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Superpowers for Dart. Collection of useful static extension methods.

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README 

        



[![Dart CI](https://github.com/leisim/dartx/workflows/Dart%20CI/badge.svg?branch=master)](https://github.com/leisim/dartx/actions) [![Codecov](https://img.shields.io/codecov/c/github/leisim/dartx.svg)](https://codecov.io/gh/leisim/dartx) [![dartx](https://img.shields.io/pub/v/dartx?label=dartx)](https://pub.dev/packages/dartx) [![flutterx](https://img.shields.io/pub/v/flutterx?label=flutterx)](https://pub.dev/packages/flutterx)



_If you miss an extension, please open an issue or pull request_



### Resources:



- [Documentation](https://pub.dev/documentation/dartx/latest/dartx/dartx-library.html)

- [Pub Package](https://pub.dev/packages/dartx)

- [GitHub Repository](https://github.com/leisim/dartx)



On this page you can find some of the extensions. Take a look at the docs to see all of them.



## Getting started πŸŽ‰



Add the following to your `pubspec.yaml`:



```dart

dependencies:

  dartx: any

```



After you import the library, you can use the extensions.



```dart

import 'package:dartx/dartx.dart';



final slice = [1, 2, 3, 4, 5].slice(1, -2); // [2, 3, 4]

```



## Iterable



### .slice()



Returns elements at indices between `start` (inclusive) and `end` (inclusive).



```dart

final list = [0, 1, 2, 3, 4, 5];

final last = list.slice(-1); // [5]

final lastHalf = list.slice(3); // [3, 4, 5]

final allButFirstAndLast = list.slice(1, -2); // [1, 2, 3, 4]

```



### .sortedBy() & .thenBy()



Sort lists by multiple properties.



```dart

final dogs = [

  Dog(name: "Tom", age: 3),

  Dog(name: "Charlie", age: 7),

  Dog(name: "Bark", age: 1),

  Dog(name: "Cookie", age: 4),

  Dog(name: "Charlie", age: 2),

];



final sorted = dogs

    .sortedBy((dog) => dog.name)

    .thenByDescending((dog) => dog.age);

// Bark, Charlie (7), Charlie (2), Cookie, Tom

```



### .distinctBy()



Get distinct elements from a list.



```dart

final list = ['this', 'is', 'a', 'test'];

final distinctByLength = list.distinctBy((it) => it.length); // ['this', 'is', 'a']

```



### .flatten()



Get a new lazy `Iterable` of all elements from all collections in a collection.



```dart

final nestedList = [[1, 2, 3], [4, 5, 6]];

final flattened = nestedList.flatten(); // [1, 2, 3, 4, 5, 6]

```



### .chunkWhile() & .splitWhen()



Chunk entries as long as two elements match a predicate:



```dart

final list = [1, 2, 4, 9, 10, 11, 12, 15, 16, 19, 20, 21];

final increasingSubSequences = list.chunkWhile((a, b) => a + 1 == b);



// increasingSubSequences = [[1, 2], [4], [9, 10, 11, 12], [15, 16], [19, 20, 21]]

```



`splitWhen` is the opposite of `chunkWhile` that starts a new chunk every time

the predicate _didn't_ match.



## int



### buildString()



Builds new string by populating newly created `StringBuffer` using provided `builderAction`

and then converting it to `String`.



```dart

final word = buildString((sb) {

  for (var i = 0; i < 10; i++) {

    sb.write(i);

  }

});

// 0123456789

```



### .ordinal



Returns an ordinal number of `String` type for any integer



```dart

final a = 1.ordinal();  // 1st

final b = 108.ordinal();  // 108th

```



## String



### .capitalize



Returns a copy of the string having its first letter uppercased, or the original string, if it's empty or already starts with an upper case letter.



```dart

final word = 'abcd'.capitalize(); // Abcd

final anotherWord = 'Abcd'.capitalize(); // Abcd

```



### .decapitalize



Returns a copy of the string having its first letter lowercased, or the original string, if it's empty or already starts with a lower case letter.



```dart

final word = 'abcd'.decapitalize(); // abcd

final anotherWord = 'Abcd'.decapitalize(); // abcd

```



### .isAscii



Returns `true` if the string is ASCII encoded.



```dart

final isAscii = 'abc123 !,.~'.isAscii; // true

final isNotAscii = 'Β§3'.isAscii; // false

```



### .isBlank



Returns `true` if this string is empty or consists solely of whitespace characters.



```dart

final notBlank = '   .'.isBlank; // false

final blank = '  '.isBlank; // true

```



### .isDouble



Returns `true` if the string can be parsed as a double.



```dart

final a = ''.isDouble; // false

final b = 'a'.isDouble; // false

final c = '1'.isDouble; // true

final d = '1.0'.isDouble; // true

final e = '123456789.987654321'.isDouble; // true

final f = '1,000'.isDouble; // false

```



### .isInt



Returns `true` if the string can be parsed as an integer.



```dart

final a = ''.isInt; // false

final b = 'a'.isInt; // false

final c = '1'.isInt; // true

final d = '1.0'.isInt; // false

final e = '1,000'.isInt; // false

```



### .isLatin1



Returns `true` if the string is Latin 1 encoded.



```dart

final isLatin1 = '§Êü'.isLatin1; // true

final isNotLatin1 = 'Ε‘'.isLatin1; // false

```



### .isLowerCase



Returns `true` if the entire string is lower case.



```dart

final a = 'abc'.isLowerCase; // true

final b = 'abC'.isLowerCase; // false

final c = '   '.isLowerCase; // true

final d = ''.isLowerCase; // false

```



### .isNotBlank



Returns `true` if this string is not empty and contains characters except whitespace characters.



```dart

final blank = '  '.isNotBlank; // false

final notBlank = '   .'.isNotBlank; // true

```



### .isNullOrEmpty



Returns `true` if the String is either `null` or empty.



```dart

final isNull = null.isNullOrEmpty; // true

final isEmpty = ''.isNullOrEmpty; // true

final isBlank = ' '.isNullOrEmpty; // false

final isLineBreak = '\n'.isNullOrEmpty; // false

```



### .isNotNullOrEmpty



Returns `true` if the String is neither `null` nor empty.



```dart

final isNull = null.isNullOrEmpty; // true

final isEmpty = ''.isNullOrEmpty; // true

final isBlank = ' '.isNullOrEmpty; // false

final isLineBreak = '\n'.isNullOrEmpty; // false

```



### .isNullOrBlank



Returns `true` if the String is either `null` or blank.



```dart

final isNull = null.isNullOrBlank; // true

final isEmpty = ''.isNullOrBlank; // true

final isBlank = ' '.isNullOrBlank; // true

final isLineBreak = '\n'.isNullOrBlank; // true

final isFoo = ' foo '.isNullOrBlank; // false

```



### .isNotNullOrBlank



Returns `true` if the String is neither `null` nor blank.



```dart

final isNull = null.isNullOrBlank; // true

final isEmpty = ''.isNullOrBlank; // true

final isBlank = ' '.isNullOrBlank; // true

final isLineBreak = '\n'.isNullOrBlank; // true

final isFoo = ' foo '.isNullOrBlank; // true

```



### .isUpperCase



Returns `true` if the entire string is upper case.



```dart

final a = 'ABC'.isUpperCase; // true

final b = 'ABc'.isUpperCase; // false

final c = '   '.isUpperCase; // true

final d = ''.isUpperCase; // false

```



### .md5



Calculates the MD5 digest and returns the value as a string of hexadecimal digits.



```dart

final a = 'abc'.md5; // 900150983cd24fb0d6963f7d28e17f72

final b = 'ΰ΄βŒ›ο€™Π‘πŸ‘¨β€πŸ‘¨β€πŸ‘§β€πŸ‘¦'.md5; // c7834eff7c967101cfb65b8f6d15ad46

```



### .urlEncode



Translates a string into application/x-www-form-urlencoded format using a specific encoding scheme.



```dart

const originalUrl = 'Hello Ladies + Gentlemen, a signed OAuth request!';

final encodedUrl = originalUrl.urlEncode;

// 'Hello%20Ladies%20+%20Gentlemen,%20a%20signed%20OAuth%20request!'

```



### .urlDecode



Decodes an application/x-www-form-urlencoded string using a specific encoding scheme.



```dart

const encodedUrl = 'Hello%20Ladies%20+%20Gentlemen,%20a%20signed%20OAuth%20request!';

final decodedUrl = encodingUrl.urlDecode;

// 'Hello Ladies + Gentlemen, a signed OAuth request!'

```



### .removePrefix(), .removeSuffix() and .removeSurrounding()



Remove a prefix, a suffix, or both from a given string:



```dart

final name = 'James Bond'.removePrefix('James '); // Bond

final milliseconds = '100ms'.removeSuffix('ms'); // 100

final text = '
Some HTML
'

  .removeSurrounding(prefix: '
', suffix: '
'); // Some HTML

```



### .reversed



Returns a new string with characters in reversed order.



```dart

final emptyString = ''.reversed; // ''

final reversed = 'abcπŸ€”'.reversed; // 'πŸ€”cba'

```



### .slice()



Returns a new substring containing all characters including indices [start] and [end].

If [end] is omitted, it is being set to `lastIndex`.



```dart

final sliceOne = 'awesomeString'.slice(0,6)); // awesome

final sliceTwo = 'awesomeString'.slice(7)); // String

```



### .toDoubleOrNull()



Parses the string as a `double` and returns the result or `null` if the String is not a valid representation of a number.



```dart

final numOne = '1'.toDoubleOrNull(); // 1.0

final numTwo = '1.2'.toDoubleOrNull(); // 1.2

final blank = ''.toDoubleOrNull(); // null

```



### .toInt()



Parses the string as an integer and returns the result. The radix (base) thereby defaults to 10. Throws a `FormatException` if parsing fails.



```dart

final a = '1'.toInt(); // 1

final b = '100'.toInt(radix: 2); // 4

final c = '100'.toInt(radix: 16); // 256

final d = '1.0'.toInt(); // throws FormatException

```



### .toIntOrNull()



Parses the string as an integer or returns `null` if it is not a number.



```dart

final number = '12345'.toIntOrNull(); // 12345

final notANumber = '123-45'.toIntOrNull(); // null

```



### .toUtf8()



Converts String to UTF-8 encoding.



```dart

final emptyString = ''.toUtf8(); // []

final hi = 'hi'.toUtf8(); // [104, 105]

final emoji = 'πŸ˜„'.toUtf8(); // [240, 159, 152, 132]



```



### .toUtf16()



Converts String to UTF-16 encoding.



```dart

final emptyString = ''.toUtf16(); // []

final hi = 'hi'.toUtf16(); // [104, 105]

final emoji = 'πŸ˜„'.toUtf16(); // [55357, 56836]

```



### .orEmpty()



Returns the string if it is not `null`, or the empty string otherwise.



```dart

String? nullableStr;

final str = nullableStr.orEmpty(); // ''

```



### .matches()



Returns `true` if this char sequence matches the given regular expression.



```dart

print('as'.matches(RegExp('^.s\$'))) // true

print('mst'.matches(RegExp('^.s\$'))) // false

```



### Time utils



Dartx exports [@jogboms](https://github.com/jogboms) great [⏰ time.dart](https://github.com/jogboms/time.dart) package so you can do the following:



```dart

int secondsInADay = 1.days.inSeconds;



Duration totalTime = [12.5.seconds, 101.milliseconds, 2.5.minutes].sum();



DateTime oneWeekLater = DateTime.now() + 1.week;

```



Check out [⏰ time.dart](https://github.com/jogboms/time.dart) for more information and examples.



## num



### .coerceIn()



Ensures that this value lies in the specified range.



```dart

final numberInRange = 123.coerceIn(0, 1000); // 123

final numberOutOfRange = -123.coerceIn(0, 1000); // 0

```



### .toBytes()



Converts this value to binary form.



### .toChar()



Converts this value to character



```dart

final character = 97.toChar(); // a

```



## range



### rangeTo



Creates a range between two ints (upwards, downwards and with custom steps)



```dart

// upwards with default step size 1

for (final i in 1.rangeTo(5)) {

  print(i); // 1, 2, 3, 4, 5

}

// downwards with custom step

for (final i in 10.rangeTo(2).step(2)) {

  print(i); // 10, 8, 6, 4, 2

}

```



## Function



### .partial(), .partial2() ...



Applies some of the required arguments to a function and returns a function which takes the remaining arguments.



```dart

void greet(String firstName, String lastName) {

  print('Hi $firstName $lastName!');

}



final greetStark = greet.partial('Stark');

greetStark('Sansa'); // Hi Sansa Stark!

greetStark('Tony'); // Hi Tony Stark!

```



## File



### .name



Get the name and extension of a file.



```dart

final file = File('some/path/testFile.dart');

print(file.name); // testFile.dart

print(file.nameWithoutExtension); // testFile

```



### .appendText()



Append text to a file.



```dart

await File('someFile.json').appendText('{test: true}');

```



### .isWithin()



Checks if a file is inside a directory.



```dart

final dir = Directory('some/path');

File('some/path/file.dart').isWithin(dir); // true

```



## Directory



### .file(String)



References a file within a `Directory`



```dart

Directory androidDir = Directory('flutter-app/android');

File manifestFile = androidDir.file("app/src/main/AndroidManifest.xml");

```



References a directory within a `Directory`



### .directory(String)



```dart

Directory androidDir = Directory('flutter-app/android');

Directory mainSrc = androidDir.directory("app/src/main");

```



### .contains(FileSystemEntity entity, {bool recursive = false})



Checks if a `Directory` contains a `FileSystemEntity`. This can be a `File` or a `Directory`.



Use the `recursive` argument to include the subdirectories.



```dart

final File someFile = File('someFile.txt');

final Directory someDir = Directory('some/dir');



final Directory parentDir = Directory('parent/dir');



parentDir.contains(someFile);

parentDir.contains(someDir);

parentDir.contains(someFile, recursive: true);

parentDir.contains(someDir, recursive: true);

```



This is the `async` method, which returns a `Future`.



### .containsSync(FileSystemEntity entity, {bool recursive = false})



Same as `.contains(FileSystemEntity entity, {bool recursive = false})` but synchronous. Returns a `bool`.



## License



```plain

Copyright 2019 Simon Leier



Licensed under the Apache License, Version 2.0 (the "License");

you may not use this file except in compliance with the License.

You may obtain a copy of the License at



   http://www.apache.org/licenses/LICENSE-2.0



Unless required by applicable law or agreed to in writing, software

distributed under the License is distributed on an "AS IS" BASIS,

WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

See the License for the specific language governing permissions and

limitations under the License.

```