dartf 0.3.0

Superpowers for Dart. A collection of useful static extension methods.

If you miss an extension, please open an issue or pull request

Resources:

• Documentation
• Pub Package
• GitHub Repository

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

Getting started

Add the following to your pubspec.yaml:

dependencies:
  dartf: any

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

import 'package:dartf/dartf.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).

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.

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

.distinctBy()

Get distinct elements from a list.

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.

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:

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.

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

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.

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.

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

.isAscii

Returns true if the string is ASCII encoded.

final isAscii = 'abc123 !,.~'.isAscii; // true
final isNotAscii = '§3'.isAscii; // false

.isBlank

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

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

.isDouble

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

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.

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.

final isLatin1 = '§Êü'.isLatin1; // true
final isNotLatin1 = 'ő'.isLatin1; // false

.isLowerCase

Returns true if the entire string is lower case.

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.

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

.isNullOrEmpty

Returns true if the String is either null or empty.

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.

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.

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.

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.

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.

final a = 'abc'.md5; // 900150983cd24fb0d6963f7d28e17f72
final b = 'ഐ⌛酪Б👨‍👨‍👧‍👦'.md5; // c7834eff7c967101cfb65b8f6d15ad46

.urlEncode

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

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.

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:

final name = 'James Bond'.removePrefix('James '); // Bond
final milliseconds = '100ms'.removeSuffix('ms'); // 100
final text = '<p>Some HTML</p>'
  .removeSurrounding(prefix: '<p>', suffix: '</p>'); // Some HTML

.reversed

Returns a new string with characters in reversed order.

final emptyString = ''.reversed; // ''
final reversed = 'abc🤔'.reversed; // '🤔cba'

.slice()

Returns a new substring containing all characters including indices [start] and [end]. If [end] is omitted, it is being set to lastIndex.

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.

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.

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.

final number = '12345'.toIntOrNull(); // 12345
final notANumber = '123-45'.toIntOrNull(); // null

.toUtf8()

Converts String to UTF-8 encoding.

final emptyString = ''.toUtf8(); // []
final hi = 'hi'.toUtf8(); // [104, 105]
final emoji = '😄'.toUtf8(); // [240, 159, 152, 132]

.toUtf16()

Converts String to UTF-16 encoding.

final emptyString = ''.toUtf16(); // []
final hi = 'hi'.toUtf16(); // [104, 105]
final emoji = '😄'.toUtf16(); // [55357, 56836]

.orEmpty()

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

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

.matches()

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

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

Time utils

dartf exports @jogboms great ⏰ time.dart package so you can do the following:

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 for more information and examples.

num

.coerceIn()

Ensures that this value lies in the specified range.

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

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

range

rangeTo

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

// 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.

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.

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

.appendText()

Append text to a file.

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

.isWithin()

Checks if a file is inside a directory.

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

Directory

.file(String)

References a file within a Directory

Directory androidDir = Directory('flutter-app/android');
File manifestFile = androidDir.file("app/src/main/AndroidManifest.xml");

References a directory within a Directory

.directory(String)

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.

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<bool>.

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

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