# Helpers
## Introduction
Nylo ships with a set of static utility classes — `Arr`, `Str`, `Number`, and `Obj` — plus a handful of global helper functions for common tasks. They are all exported from `nylo_framework`:
``` dart
import 'package:nylo_framework/nylo_framework.dart';
Arr.first([1, 2, 3]); // 1
Str.slug('Hello World'); // 'hello-world'
Number.currency(1234.56); // '$1,234.56'
Obj.get(user, 'profile.name'); // 'Anna'
```
> **Note:** `Backpack`, `NyStorage`, `NyCache`, and `NyLogger` have their own dedicated pages: [Backpack](/docs/7.x/backpack), [Storage](/docs/7.x/storage), [Cache](/docs/7.x/cache), [Logging](/docs/7.x/logging).
## Available Methods
### Arrays
### Strings
### Numbers
### Objects
### Miscellaneous
## Arrays
#### `Arr.accessible()`
Determines whether the given value is array-accessible (a `List` or `Map`):
``` dart
Arr.accessible([1, 2, 3]); // true
Arr.accessible({'a': 1}); // true
Arr.accessible('hello'); // false
Arr.accessible(null); // false
```
#### `Arr.average()`
Returns the arithmetic mean of the list, or `0` when empty. Pass `by` to extract a number from each element:
``` dart
Arr.average([2, 4, 6]); // 4.0
Arr.average(orders, by: (o) => o.total); // mean total
```
#### `Arr.chunk()`
Splits a list into chunks of the given size:
``` dart
Arr.chunk([1, 2, 3, 4, 5], 2);
// [[1, 2], [3, 4], [5]]
```
#### `Arr.collapse()`
Collapses a list of lists into a single list:
``` dart
Arr.collapse([[1, 2], [3, 4], [5]]);
// [1, 2, 3, 4, 5]
```
#### `Arr.countBy()`
Counts occurrences in the list, optionally grouping by a value extractor:
``` dart
Arr.countBy(['a', 'b', 'a', 'c']);
// {'a': 2, 'b': 1, 'c': 1}
Arr.countBy(orders, by: (o) => o.status);
// {'paid': 12, 'pending': 3}
```
#### `Arr.crossJoin()`
Cross-joins the given lists, returning every possible combination:
``` dart
Arr.crossJoin([[1, 2], ['a', 'b']]);
// [[1, 'a'], [1, 'b'], [2, 'a'], [2, 'b']]
```
#### `Arr.every()`
Returns `true` when every element of the list passes the predicate. Vacuously true for empty lists:
``` dart
Arr.every([2, 4, 6], (n) => n.isEven); // true
Arr.every([1, 2, 3], (n) => n.isEven); // false
```
#### `Arr.exceptValues()`
Returns the list with each of the given values removed:
``` dart
Arr.exceptValues([1, 2, 3, 4], [2, 4]); // [1, 3]
```
#### `Arr.first()`
Returns the first element matching the predicate, or the default value:
``` dart
Arr.first([1, 2, 3]); // 1
Arr.first([1, 2, 3, 4], predicate: (n) => n.isEven); // 2
Arr.first([], defaultValue: 99); // 99
```
#### `Arr.flatMap()`
Maps each element through `fn` and flattens the resulting iterables:
``` dart
Arr.flatMap(pages, (p) => p.items); // all items from all pages
Arr.flatMap([1, 2, 3], (n) => [n, n * 10]); // [1, 10, 2, 20, 3, 30]
```
#### `Arr.flatten()`
Flattens a nested iterable into a single-level list. `depth` limits how deep to flatten; `-1` means unlimited:
``` dart
Arr.flatten([1, [2, [3]]]); // [1, 2, 3]
Arr.flatten([1, [2, [3]]], depth: 1); // [1, 2, [3]]
```
#### `Arr.groupBy()`
Groups the list into a map keyed by the value returned by `by`:
``` dart
Arr.groupBy(messages, (m) => m.date);
// {2024-01-01: [...], 2024-01-02: [...]}
```
#### `Arr.indexed()`
Pairs each element with its index, returning a list of `(index, value)` records:
``` dart
for (final (i, v) in Arr.indexed(['a', 'b', 'c'])) {
print('$i: $v'); // '0: a', '1: b', '2: c'
}
```
#### `Arr.interleave()`
Inserts a separator between every pair of elements. Useful for building widget children with separators:
``` dart
Arr.interleave([1, 2, 3], 0); // [1, 0, 2, 0, 3]
Column(children: Arr.interleave(tiles, const Divider()));
```
#### `Arr.isAssoc()`
Returns `true` when the value is a `Map` (associative):
``` dart
Arr.isAssoc({'a': 1}); // true
Arr.isAssoc([1, 2, 3]); // false
```
#### `Arr.isList()`
Returns `true` when the value is a `List`:
``` dart
Arr.isList([1, 2, 3]); // true
Arr.isList({'a': 1}); // false
```
#### `Arr.join()`
Joins the list into a string. The final element can be joined with a different separator:
``` dart
Arr.join(['Anna', 'Brad', 'Carol'], ', ', ' and ');
// 'Anna, Brad and Carol'
Arr.join(['a', 'b', 'c']);
// 'a, b, c'
```
#### `Arr.keyBy()`
Indexes the list by the value at a key. Entries with a `null` value at that key are skipped:
``` dart
Arr.keyBy([
{'id': 1, 'name': 'Anna'},
{'id': 2, 'name': 'Brad'},
], 'id');
// {1: {'id': 1, 'name': 'Anna'}, 2: {'id': 2, 'name': 'Brad'}}
```
#### `Arr.last()`
Returns the last element matching the predicate, or the default value:
``` dart
Arr.last([1, 2, 3, 4], predicate: (n) => n.isEven); // 4
Arr.last([1, 2, 3]); // 3
```
#### `Arr.map()`
Maps each element through a callback that also receives the index:
``` dart
Arr.map(['a', 'b'], (v, i) => '$i:$v'); // ['0:a', '1:b']
```
#### `Arr.mapWithKeys()`
Maps each element to a `MapEntry`, returning the resulting map:
``` dart
Arr.mapWithKeys(
[{'id': 1, 'name': 'Anna'}, {'id': 2, 'name': 'Brad'}],
(m) => MapEntry(m['id'], m['name']),
);
// {1: 'Anna', 2: 'Brad'}
```
#### `Arr.max()`
Returns the element with the largest value of `by`, or the largest element when `by` is omitted:
``` dart
Arr.max([3, 1, 4, 1, 5]); // 5
Arr.max(users, by: (u) => u.age); // user with the highest age
```
#### `Arr.median()`
Returns the median of the list, or `0` when empty:
``` dart
Arr.median([1, 3, 5]); // 3.0
Arr.median([1, 2, 3, 4]); // 2.5
```
#### `Arr.min()`
Returns the element with the smallest value of `by`, or the smallest element when `by` is omitted:
``` dart
Arr.min([3, 1, 4, 1, 5]); // 1
Arr.min(users, by: (u) => u.age); // user with the youngest age
```
#### `Arr.move()`
Returns a new list with the element at `from` moved to position `to`. `to` is clamped to the valid range:
``` dart
Arr.move(['a', 'b', 'c', 'd'], 0, 2); // ['b', 'c', 'a', 'd']
```
#### `Arr.onlyValues()`
Returns the elements of the list that are also in the given values:
``` dart
Arr.onlyValues([1, 2, 3, 4], [2, 4, 9]); // [2, 4]
```
#### `Arr.partition()`
Splits the list into a `[matching, nonMatching]` pair based on the predicate:
``` dart
final [evens, odds] = Arr.partition([1, 2, 3, 4], (n) => n.isEven);
// evens: [2, 4], odds: [1, 3]
```
#### `Arr.pluck()`
Plucks the value at a key from each map in the list:
``` dart
Arr.pluck([
{'name': 'Anna'},
{'name': 'Brad'},
], 'name');
// ['Anna', 'Brad']
```
#### `Arr.prepend()`
Returns a new list with the value inserted at the front:
``` dart
Arr.prepend([2, 3], 1); // [1, 2, 3]
```
#### `Arr.push()`
Returns a new list with the value appended at the end:
``` dart
Arr.push([1, 2], 3); // [1, 2, 3]
```
#### `Arr.random()`
Returns a random element of the list. Throws when the list is empty:
``` dart
Arr.random(['rock', 'paper', 'scissors']); // one of the three
```
#### `Arr.randomMany()`
Returns up to `count` random elements without replacement:
``` dart
Arr.randomMany([1, 2, 3, 4, 5], 2); // e.g. [3, 1]
```
#### `Arr.reject()`
Filters the list to elements *not* matching the predicate (the inverse of [`where`](#method-arr-where)):
``` dart
Arr.reject([1, 2, 3, 4], (n) => n.isEven); // [1, 3]
```
#### `Arr.replaceAt()`
Returns a new list with the element at `index` replaced by `value`. Throws `RangeError` when `index` is out of range:
``` dart
Arr.replaceAt(['a', 'b', 'c'], 1, 'B'); // ['a', 'B', 'c']
```
#### `Arr.select()`
Returns each map in the list reduced to only the given keys:
``` dart
Arr.select([
{'name': 'Anna', 'role': 'admin', 'age': 30},
{'name': 'Brad', 'role': 'user', 'age': 25},
], ['name', 'role']);
// [{'name': 'Anna', 'role': 'admin'}, {'name': 'Brad', 'role': 'user'}]
```
#### `Arr.shuffle()`
Returns a shuffled copy of the list. Pass `seed` for determinism:
``` dart
Arr.shuffle([1, 2, 3, 4, 5]);
Arr.shuffle([1, 2, 3], seed: 42); // deterministic
```
#### `Arr.sole()`
Returns the single element matching the predicate. Throws when zero or more than one element matches:
``` dart
Arr.sole([1, 2, 3, 4], predicate: (n) => n == 3); // 3
Arr.sole([1, 2, 3], predicate: (n) => n.isEven); // 2
```
#### `Arr.some()`
Returns `true` when at least one element passes the predicate:
``` dart
Arr.some([1, 2, 3], (n) => n.isEven); // true
Arr.some([1, 3, 5], (n) => n.isEven); // false
```
#### `Arr.sort()`
Returns a sorted copy of the list:
``` dart
Arr.sort([3, 1, 2]); // [1, 2, 3]
Arr.sort(users, compare: (a, b) => a.age - b.age); // by age asc
```
#### `Arr.sortDesc()`
Returns a sorted copy of the list in descending order:
``` dart
Arr.sortDesc([3, 1, 2]); // [3, 2, 1]
```
#### `Arr.sortRecursive()`
Recursively sorts the list. Nested lists are sorted at every depth:
``` dart
Arr.sortRecursive([[3, 1, 2], [9, 7, 8]]);
// [[1, 2, 3], [7, 8, 9]]
```
#### `Arr.sum()`
Returns the sum of the list. Pass `by` to extract a number from each element:
``` dart
Arr.sum([1, 2, 3]); // 6
Arr.sum(orders, by: (o) => o.total); // sum of totals
```
#### `Arr.swap()`
Returns a new list with the elements at `i` and `j` swapped:
``` dart
Arr.swap(['a', 'b', 'c'], 0, 2); // ['c', 'b', 'a']
```
#### `Arr.take()`
Returns the first `count` elements, or the last `count` if `count` is negative:
``` dart
Arr.take([1, 2, 3, 4, 5], 2); // [1, 2]
Arr.take([1, 2, 3, 4, 5], -2); // [4, 5]
```
#### `Arr.unique()`
Returns the unique values of the list:
``` dart
Arr.unique([1, 2, 2, 3, 1]); // [1, 2, 3]
```
#### `Arr.where()`
Filters the list to elements matching the predicate:
``` dart
Arr.where([1, 2, 3, 4], (n) => n.isEven); // [2, 4]
```
#### `Arr.whereNotNull()`
Returns the list with `null` values removed:
``` dart
Arr.whereNotNull([1, null, 2, null, 3]); // [1, 2, 3]
```
#### `Arr.wrap()`
Wraps a value in a `List` if it isn't one already. Returns an empty list when the value is `null`:
``` dart
Arr.wrap('foo'); // ['foo']
Arr.wrap([1, 2]); // [1, 2]
Arr.wrap(null); // []
```
## Strings
#### `Str.after()`
Returns the portion of `subject` after the first occurrence of `search`:
``` dart
Str.after('hello world hello', 'hello'); // ' world hello'
```
#### `Str.afterLast()`
Returns the portion of `subject` after the last occurrence of `search`:
``` dart
Str.afterLast('app/Http/Controllers', '/'); // 'Controllers'
```
#### `Str.before()`
Returns the portion of `subject` before the first occurrence of `search`:
``` dart
Str.before('hello world', ' '); // 'hello'
```
#### `Str.beforeLast()`
Returns the portion of `subject` before the last occurrence of `search`:
``` dart
Str.beforeLast('app/Http/Controllers', '/'); // 'app/Http'
```
#### `Str.between()`
Returns the portion of `subject` between `from` and `to` (greedy):
``` dart
Str.between('[a] foo [b]', '[', ']'); // 'a] foo [b'
```
#### `Str.betweenFirst()`
Returns the smallest portion of `subject` between `from` and `to`:
``` dart
Str.betweenFirst('[a] foo [b]', '[', ']'); // 'a'
```
#### `Str.camel()`
Converts the value to `camelCase`:
``` dart
Str.camel('foo_bar'); // 'fooBar'
Str.camel('Hello world'); // 'helloWorld'
```
#### `Str.charAt()`
Returns the character at the given index. Negative indexes count from the end. Returns `null` when out of range:
``` dart
Str.charAt('hello', 1); // 'e'
Str.charAt('hello', -1); // 'o'
Str.charAt('hello', 99); // null
```
#### `Str.contains()`
Determines whether `haystack` contains any of the `needles`:
``` dart
Str.contains('hello world', 'world'); // true
Str.contains('hello world', ['cat', 'world']); // true
Str.contains('Hello', 'hello', ignoreCase: true); // true
```
#### `Str.containsAll()`
Determines whether `haystack` contains all of the `needles`:
``` dart
Str.containsAll('hello world', ['hello', 'world']); // true
Str.containsAll('hello world', ['hello', 'cat']); // false
```
#### `Str.deduplicate()`
Replaces consecutive runs of `character` with a single instance:
``` dart
Str.deduplicate('hello world'); // 'hello world'
Str.deduplicate('//path//to//', '/'); // '/path/to/'
```
#### `Str.endsWith()`
Determines whether `haystack` ends with any of the `needles`:
``` dart
Str.endsWith('app.dart', '.dart'); // true
Str.endsWith('app.dart', ['.dart', '.ts']); // true
```
#### `Str.excerpt()`
Extracts a snippet of text around the first occurrence of `phrase`. Returns `null` when the phrase is not found:
``` dart
Str.excerpt(
'This is my favorite quote of all time.',
'favorite',
radius: 5,
);
// '...is my favorite quote ...'
```
#### `Str.finish()`
Caps the value with a single instance of `cap`:
``` dart
Str.finish('hello', '!'); // 'hello!'
Str.finish('hello!!!', '!'); // 'hello!'
```
#### `Str.headline()`
Splits a string into words on uppercase boundaries, underscores, hyphens, and whitespace, then converts to title case:
``` dart
Str.headline('steve_jobs'); // 'Steve Jobs'
Str.headline('EmailNotificationSent'); // 'Email Notification Sent'
```
#### `Str.is_()`
Determines whether the value matches the given pattern. Asterisks act as wildcards:
``` dart
Str.is_('foo.*', 'foo.bar'); // true
Str.is_(['admin/*', 'user/*'], 'admin/profile'); // true
Str.is_('foo', 'bar'); // false
```
> **Note:** The trailing underscore avoids the reserved Dart keyword `is`.
#### `Str.isAscii()`
Returns `true` if the value contains only 7-bit ASCII characters:
``` dart
Str.isAscii('hello'); // true
Str.isAscii('héllo'); // false
```
#### `Str.isJson()`
Returns `true` if the value is valid JSON:
``` dart
Str.isJson('{"a": 1}'); // true
Str.isJson('not json'); // false
```
#### `Str.isUlid()`
Returns `true` if the value is a ULID (26 chars, Crockford base32):
``` dart
Str.isUlid('01ARZ3NDEKTSV4RRFFQ69G5FAV'); // true
Str.isUlid('not a ulid'); // false
```
#### `Str.isUrl()`
Returns `true` if the value is a valid URL:
``` dart
Str.isUrl('https://nylo.dev'); // true
Str.isUrl('not a url'); // false
```
#### `Str.isUuid()`
Returns `true` if the value is a valid UUID (any version):
``` dart
Str.isUuid('a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11'); // true
Str.isUuid('hello'); // false
```
#### `Str.kebab()`
Converts the value to `kebab-case`:
``` dart
Str.kebab('fooBar'); // 'foo-bar'
Str.kebab('Hello World'); // 'hello-world'
```
#### `Str.lcfirst()`
Lowercases the first character of the value:
``` dart
Str.lcfirst('Hello world'); // 'hello world'
```
#### `Str.length()`
Returns the length of the value:
``` dart
Str.length('hello'); // 5
```
#### `Str.limit()`
Truncates the value to the given number of characters and appends a suffix:
``` dart
Str.limit('A long sentence', 6); // 'A long...'
Str.limit('A long sentence', 6, '... read'); // 'A long... read'
```
#### `Str.lower()`
Lowercases the value:
``` dart
Str.lower('HELLO'); // 'hello'
```
#### `Str.mask()`
Masks a portion of the string with a character, starting at `index` for `length` chars (or to the end when `length` is omitted):
``` dart
Str.mask('user@example.com', '*', 3); // 'use*************'
Str.mask('user@example.com', '*', 3, 5); // 'use*****mple.com'
```
#### `Str.match()`
Returns the first regex match of `pattern` in `subject`, or `null` when there is no match:
``` dart
Str.match(RegExp(r'\d+'), 'item 42 in 99 stock'); // '42'
```
> **Note:** This is a regex matcher — distinct from the global [`match`](#method-match) helper used for `Map`-based value lookups.
#### `Str.matchAll()`
Returns all regex matches of `pattern` in `subject`:
``` dart
Str.matchAll(RegExp(r'\d+'), 'item 42 in 99 stock'); // ['42', '99']
```
#### `Str.padBoth()`
Pads both sides of the value with `pad` until `length` is reached:
``` dart
Str.padBoth('5', 5, '0'); // '00500'
```
#### `Str.padLeft()`
Pads the left side of the value:
``` dart
Str.padLeft('5', 3, '0'); // '005'
```
#### `Str.padNumber()`
Pads a numeric string with leading zeros:
``` dart
Str.padNumber('5', 3); // '005'
```
#### `Str.padRight()`
Pads the right side of the value:
``` dart
Str.padRight('5', 3, '0'); // '500'
```
#### `Str.password()`
Generates a cryptographically random password. Toggle character classes via the named arguments:
``` dart
Str.password(12); // letters + numbers + symbols
Str.password(12, symbols: false); // letters + numbers only
Str.password(8, letters: false, symbols: false); // digits only
```
#### `Str.position()`
Returns the index of the first occurrence of `needle` in `haystack`, or `null` when not found:
``` dart
Str.position('hello world', 'world'); // 6
Str.position('hello world hello', 'hello', offset: 1); // 12
Str.position('hello', 'cat'); // null
```
#### `Str.random()`
Generates a cryptographically random alphanumeric string of the given length:
``` dart
Str.random(); // 16 chars, e.g. 'aB3k9XzMq7VnPsRt'
Str.random(8); // 8 chars
```
#### `Str.remove()`
Removes any of `search` from `subject`:
``` dart
Str.remove('o', 'hello world'); // 'hell wrld'
Str.remove(['e', 'l'], 'hello world'); // 'ho word'
Str.remove('Hello', 'hello world', caseSensitive: false); // ' world'
```
#### `Str.repeat()`
Repeats the value the given number of times:
``` dart
Str.repeat('ab', 3); // 'ababab'
```
#### `Str.replace()`
Replaces every occurrence of `search` with `replace` in `subject`:
``` dart
Str.replace('o', '0', 'hello world'); // 'hell0 w0rld'
Str.replace(['o', 'l'], '*', 'hello world'); // 'he*** w*r*d'
```
#### `Str.replaceFirst()`
Replaces the first occurrence of `search` with `replace`:
``` dart
Str.replaceFirst('hello', 'hi', 'hello hello'); // 'hi hello'
```
#### `Str.replaceLast()`
Replaces the last occurrence of `search` with `replace`:
``` dart
Str.replaceLast('hello', 'hi', 'hello hello'); // 'hello hi'
```
#### `Str.reverse()`
Reverses the value:
``` dart
Str.reverse('hello'); // 'olleh'
```
#### `Str.slug()`
Generates a URL-friendly slug from the title:
``` dart
Str.slug('Hello World'); // 'hello-world'
Str.slug('Tech & Code', dictionary: {'&': 'and'}); // 'tech-and-code'
Str.slug('Hello World', separator: '_'); // 'hello_world'
```
#### `Str.snake()`
Converts the value to `snake_case`. Pass a custom delimiter to use something other than `_`:
``` dart
Str.snake('helloWorld'); // 'hello_world'
Str.snake('helloWorld', '-'); // 'hello-world'
```
#### `Str.squish()`
Trims leading/trailing whitespace and collapses internal whitespace into single spaces:
``` dart
Str.squish(' hello world '); // 'hello world'
```
#### `Str.start()`
Begins the value with a single instance of `prefix`:
``` dart
Str.start('this/string', '/'); // '/this/string'
Str.start('//this/string', '/'); // '/this/string'
```
#### `Str.startsWith()`
Determines whether `haystack` starts with any of the `needles`:
``` dart
Str.startsWith('hello world', 'hello'); // true
Str.startsWith('hello world', ['cat', 'hello']); // true
```
#### `Str.studly()`
Converts the value to `StudlyCase` / `PascalCase`:
``` dart
Str.studly('foo_bar'); // 'FooBar'
Str.studly('hello world'); // 'HelloWorld'
```
#### `Str.substr()`
Returns a substring starting at `start` for `length` characters. Negative `start` counts from the end:
``` dart
Str.substr('profile', 4); // 'ile'
Str.substr('profile', 4, 2); // 'il'
Str.substr('profile', -3); // 'ile'
```
#### `Str.substrCount()`
Counts non-overlapping occurrences of `needle` in `haystack`:
``` dart
Str.substrCount('hello hello hello', 'hello'); // 3
```
#### `Str.swap()`
Replaces multiple substrings using a `Map` of search → replace pairs:
``` dart
Str.swap({'foo': 'bar', 'hello': 'hi'}, 'hello foo'); // 'hi bar'
```
#### `Str.take()`
Returns the first `limit` characters of the value. A negative limit returns from the end:
``` dart
Str.take('Build something amazing!', 5); // 'Build'
Str.take('Build something amazing!', -9); // ' amazing!'
```
#### `Str.title()`
Converts the value to `Title Case`:
``` dart
Str.title('a nice title'); // 'A Nice Title'
```
#### `Str.ucfirst()`
Uppercases the first character of the value:
``` dart
Str.ucfirst('hello world'); // 'Hello world'
```
#### `Str.ucsplit()`
Splits the value into words on uppercase boundaries:
``` dart
Str.ucsplit('fooBarBaz'); // ['foo', 'Bar', 'Baz']
```
#### `Str.ulid()`
Generates a ULID (Universally Unique Lexicographically Sortable Identifier):
``` dart
Str.ulid(); // e.g. '01ARZ3NDEKTSV4RRFFQ69G5FAV'
```
#### `Str.unwrap()`
Strips a single instance of `before` from the start and `after` (or `before` if `after` is null) from the end:
``` dart
Str.unwrap('"value"', '"'); // 'value'
Str.unwrap('html
', '', '
'); // 'html'
```
#### `Str.upper()`
Uppercases the value:
``` dart
Str.upper('hello'); // 'HELLO'
```
#### `Str.uuid()`
Generates a random UUID v4:
``` dart
Str.uuid(); // e.g. 'a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11'
```
#### `Str.uuid7()`
Generates a UUID v7 (time-ordered, RFC 9562). UUIDv7s are sortable by creation time:
``` dart
Str.uuid7(); // e.g. '018e0dc4-8b3f-7a2c-9d01-b1f6c87a92e3'
```
#### `Str.wordCount()`
Returns the word count of the value:
``` dart
Str.wordCount('hello there friend'); // 3
```
#### `Str.words()`
Limits the value to the given number of words:
``` dart
Str.words('Perfectly balanced, as all things should be.', 3);
// 'Perfectly balanced, as...'
```
#### `Str.wrap()`
Wraps the value with `before` and `after`. When `after` is omitted, `before` is used on both sides:
``` dart
Str.wrap('value', '"'); // '"value"'
Str.wrap('html', '', '
'); // 'html
'
```
## Numbers
#### `Number.abbreviate()`
Returns an abbreviated form of the number (`1K`, `1M`, `1B`):
``` dart
Number.abbreviate(1500); // '2K'
Number.abbreviate(1500, maxPrecision: 1); // '1.5K'
Number.abbreviate(2_500_000); // '3M'
```
#### `Number.average()`
Returns the arithmetic mean of the values, or `0` when empty:
``` dart
Number.average([1, 2, 3, 4]); // 2.5
```
#### `Number.between()`
Returns `true` when the value is between `min` and `max` (inclusive):
``` dart
Number.between(5, min: 0, max: 10); // true
Number.between(15, min: 0, max: 10); // false
```
#### `Number.ceil()`
Ceils the value to the given precision:
``` dart
Number.ceil(1.2); // 2.0
Number.ceil(1.234, 2); // 1.24
```
#### `Number.clamp()`
Clamps a value between `min` and `max` (inclusive):
``` dart
Number.clamp(5, 0, 10); // 5
Number.clamp(15, 0, 10); // 10
Number.clamp(-1, 0, 10); // 0
```
#### `Number.currency()`
Formats the number as a currency value. Defaults to the configured locale and currency:
``` dart
Number.currency(1234.56); // '$1,234.56'
Number.currency(1234.56, currency: 'EUR'); // '€1,234.56'
Number.currency(1234.56, locale: 'de_DE', currency: 'EUR');
// '1.234,56 €'
```
#### `Number.defaultCurrency()`
Returns the default currency code used by formatting methods:
``` dart
Number.defaultCurrency(); // 'USD'
```
#### `Number.defaultLocale()`
Returns the default locale used by formatting methods:
``` dart
Number.defaultLocale(); // 'en_US'
```
#### `Number.degrees()`
Converts radians to degrees:
``` dart
Number.degrees(3.14159); // ~180.0
```
#### `Number.duration()`
Formats a number of seconds as a human-readable duration. The short form returns `'1h 2m 5s'`; the long form returns `'1:02:05'`:
``` dart
Number.duration(3661); // '1h 1m 1s'
Number.duration(3661, short: false); // '1:01:01'
Number.duration(45); // '45s'
```
#### `Number.fileSize()`
Formats a byte count as a human-readable file size:
``` dart
Number.fileSize(1024); // '1 KB'
Number.fileSize(1500, maxPrecision: 1); // '1.5 KB'
Number.fileSize(1024 * 1024 * 1024); // '1 GB'
```
#### `Number.floor()`
Floors the value to the given precision:
``` dart
Number.floor(1.7); // 1.0
Number.floor(1.234, 2); // 1.23
```
#### `Number.forHumans()`
Returns a human-readable form of the number (`1 thousand`, `1 million`):
``` dart
Number.forHumans(1500); // '2 thousand'
Number.forHumans(1500, maxPrecision: 1); // '1.5 thousand'
Number.forHumans(2_500_000); // '3 million'
```
#### `Number.format()`
Formats the number with locale-aware separators:
``` dart
Number.format(1234567); // '1,234,567'
Number.format(1234.5, precision: 2); // '1,234.50'
Number.format(1234567, locale: 'de_DE'); // '1.234.567'
```
#### `Number.gcd()`
Greatest common divisor of two integers:
``` dart
Number.gcd(12, 18); // 6
```
#### `Number.lcm()`
Least common multiple of two integers:
``` dart
Number.lcm(4, 6); // 12
```
#### `Number.lerp()`
Linearly interpolates between `a` and `b` by `t` (`0..1`):
``` dart
Number.lerp(0, 100, 0.25); // 25.0
```
#### `Number.max()`
Returns the largest value in the iterable:
``` dart
Number.max([3, 1, 4, 1, 5, 9, 2, 6]); // 9
```
#### `Number.median()`
Returns the median of the values, or `0` when empty:
``` dart
Number.median([1, 3, 5]); // 3.0
Number.median([1, 2, 3, 4]); // 2.5
```
#### `Number.min()`
Returns the smallest value in the iterable:
``` dart
Number.min([3, 1, 4, 1, 5, 9, 2, 6]); // 1
```
#### `Number.ordinal()`
Returns the ordinal form of the number (`1st`, `2nd`, `3rd`, `4th`):
``` dart
Number.ordinal(1); // '1st'
Number.ordinal(2); // '2nd'
Number.ordinal(21); // '21st'
Number.ordinal(112); // '112th'
```
#### `Number.pairs()`
Generates pairs (sub-ranges) from a range up to `to`, stepping by `by`:
``` dart
Number.pairs(25, 10); // [[0, 9], [10, 19], [20, 25]]
Number.pairs(25, 10, offset: 0); // [[0, 10], [10, 20], [20, 25]]
```
#### `Number.parseFloat()`
Parses a locale-aware string as a `double`. Returns `null` on failure:
``` dart
Number.parseFloat('1,234.56'); // 1234.56
Number.parseFloat('1.234,56', locale: 'de_DE'); // 1234.56
Number.parseFloat('not a number'); // null
```
#### `Number.parseInt()`
Parses a locale-aware string as an `int`. Returns `null` on failure:
``` dart
Number.parseInt('1,234'); // 1234
Number.parseInt('1.234', locale: 'de_DE'); // 1234
```
#### `Number.percentage()`
Formats the number as a percentage. The number is treated as the whole percentage value:
``` dart
Number.percentage(10); // '10%'
Number.percentage(10.5, precision: 1); // '10.5%'
```
#### `Number.radians()`
Converts degrees to radians:
``` dart
Number.radians(180); // ~3.14159
```
#### `Number.random()`
Returns a random integer in `[min, max]` (inclusive). Pass `seed` for a deterministic sequence:
``` dart
Number.random(min: 1, max: 100); // any int 1..100
Number.random(min: 0, max: 9, seed: 42); // deterministic
```
#### `Number.range()`
Generates a list of integers from `start` (inclusive) to `end` (inclusive), stepping by `step`:
``` dart
Number.range(1, 5); // [1, 2, 3, 4, 5]
Number.range(0, 10, step: 2); // [0, 2, 4, 6, 8, 10]
Number.range(5, 1, step: -1); // [5, 4, 3, 2, 1]
```
#### `Number.round()`
Rounds the value to the given precision:
``` dart
Number.round(1.5); // 2.0
Number.round(1.234, 2); // 1.23
```
#### `Number.scale()`
Re-maps a value from one range to another:
``` dart
Number.scale(0.5, fromMin: 0, fromMax: 1, toMin: 0, toMax: 100); // 50.0
Number.scale(75, fromMin: 0, fromMax: 100, toMin: -1, toMax: 1); // 0.5
```
#### `Number.spell()`
Spells out the number in English:
``` dart
Number.spell(0); // 'zero'
Number.spell(123); // 'one hundred twenty-three'
Number.spell(1_234_567); // 'one million two hundred thirty-four thousand five hundred sixty-seven'
```
#### `Number.spellOrdinal()`
Spells out the ordinal form of the number in English:
``` dart
Number.spellOrdinal(1); // 'first'
Number.spellOrdinal(2); // 'second'
Number.spellOrdinal(21); // 'twenty-first'
```
#### `Number.sum()`
Returns the sum of the values:
``` dart
Number.sum([1, 2, 3]); // 6
```
#### `Number.toBytes()`
Converts a file size to bytes. Inverse of [`fileSize`](#method-number-filesize). Pass either a parseable string or a number with `unit`:
``` dart
Number.toBytes('1.5 KB'); // 1536
Number.toBytes(1.5, 'KB'); // 1536
Number.toBytes(1, 'GB'); // 1073741824
Number.toBytes('not bytes'); // null
```
#### `Number.trim()`
Removes trailing zeros from the decimal portion of the value:
``` dart
Number.trim(12.0); // '12'
Number.trim(12.30); // '12.3'
Number.trim(12.345); // '12.345'
```
#### `Number.useCurrency()`
Sets the default currency code used by formatting methods:
``` dart
Number.useCurrency('EUR');
Number.currency(99); // '€99.00'
```
#### `Number.useLocale()`
Sets the default locale used by formatting methods:
``` dart
Number.useLocale('de_DE');
Number.format(1234567); // '1.234.567'
```
## Objects
`Obj` provides utilities for working with maps using **dot-notation** paths. List elements can be addressed by integer index (e.g. `'users.0.name'`).
#### `Obj.add()`
Adds a value at `key` only when no value currently exists there:
``` dart
final user = {'name': 'Anna'};
Obj.add(user, 'role', 'admin');
// user: {'name': 'Anna', 'role': 'admin'}
Obj.add(user, 'name', 'Brad'); // no-op — name already set
```
#### `Obj.deepEquals()`
Returns `true` when two values are structurally equal (recursive comparison of `Map`s and `List`s):
``` dart
Obj.deepEquals({'a': [1, 2]}, {'a': [1, 2]}); // true
Obj.deepEquals({'a': 1}, {'a': 2}); // false
```
#### `Obj.divide()`
Splits a map into a `[keys, values]` pair:
``` dart
Obj.divide({'name': 'Desk', 'price': 100});
// [['name', 'price'], ['Desk', 100]]
```
#### `Obj.dot()`
Flattens a nested map into a single-level map keyed by dot-paths:
``` dart
Obj.dot({'a': {'b': 1, 'c': 2}});
// {'a.b': 1, 'a.c': 2}
```
#### `Obj.except()`
Returns a new map containing all entries except those with the given keys:
``` dart
Obj.except({'name': 'Anna', 'role': 'admin', 'age': 30}, ['age']);
// {'name': 'Anna', 'role': 'admin'}
```
#### `Obj.exists()`
Returns `true` when the map has the given key at the top level (no dot-notation traversal):
``` dart
Obj.exists({'a.b': 1}, 'a.b'); // true
Obj.exists({'a': {'b': 1}}, 'a.b'); // false (use `has` for traversal)
```
#### `Obj.flip()`
Swaps keys and values. When values collide, the last entry wins:
``` dart
Obj.flip({'one': 1, 'two': 2}); // {1: 'one', 2: 'two'}
```
#### `Obj.forget()`
Removes a key (dot notation) from the map. Returns the map for chaining:
``` dart
final user = {'profile': {'name': 'Anna', 'email': 'a@b'}};
Obj.forget(user, 'profile.email');
// user: {'profile': {'name': 'Anna'}}
```
#### `Obj.get()`
Returns the value at `key` using dot notation, or the default value when the path is missing. Top-level keys containing literal dots take precedence over traversal:
``` dart
final user = {'profile': {'name': 'Anna', 'age': 30}};
Obj.get(user, 'profile.name'); // 'Anna'
Obj.get(user, 'profile.email'); // null
Obj.get(user, 'profile.email', 'unknown'); // 'unknown'
// List indices:
Obj.get({'users': [{'name': 'A'}]}, 'users.0.name'); // 'A'
```
#### `Obj.getBool()`
Returns the value at `key` coerced to `bool`, or the default value. Numbers are truthy when non-zero; strings recognize `'true'`/`'false'`/`'1'`/`'0'`/`'yes'`/`'no'`/`'on'`/`'off'` (case-insensitive):
``` dart
Obj.getBool({'flag': 'yes'}, 'flag'); // true
Obj.getBool({'flag': 0}, 'flag'); // false
Obj.getBool({}, 'flag', false); // false
```
#### `Obj.getDouble()`
Returns the value at `key` coerced to `double`, or the default value:
``` dart
Obj.getDouble({'price': '9.99'}, 'price'); // 9.99
Obj.getDouble({'price': 10}, 'price'); // 10.0
```
#### `Obj.getInt()`
Returns the value at `key` coerced to `int`, or the default value:
``` dart
Obj.getInt({'count': '42'}, 'count'); // 42
Obj.getInt({'count': 3.7}, 'count'); // 3 (truncated)
Obj.getInt({}, 'count', 0); // 0
```
#### `Obj.getList()`
Returns the value at `key` when it is a `List`, otherwise the default value:
``` dart
Obj.getList({'items': [1, 2, 3]}, 'items'); // [1, 2, 3]
Obj.getList({'items': 'oops'}, 'items', []); // []
```
#### `Obj.getMap()`
Returns the value at `key` when it is a `Map`, otherwise the default value:
``` dart
Obj.getMap({'meta': {'a': 1}}, 'meta'); // {'a': 1}
Obj.getMap({'meta': null}, 'meta', {}); // {}
```
#### `Obj.getString()`
Returns the value at `key` coerced to `String`, or the default value:
``` dart
Obj.getString({'name': 'Anna'}, 'name'); // 'Anna'
Obj.getString({'count': 42}, 'count'); // '42'
Obj.getString({}, 'name', 'Guest'); // 'Guest'
```
#### `Obj.has()`
Returns `true` when the map has a value at `key` using dot notation:
``` dart
final user = {'profile': {'name': 'Anna'}};
Obj.has(user, 'profile.name'); // true
Obj.has(user, 'profile.email'); // false
```
#### `Obj.hasAll()`
Returns `true` when every one of the given keys resolves in the map:
``` dart
Obj.hasAll({'a': 1, 'b': 2}, ['a', 'b']); // true
Obj.hasAll({'a': 1, 'b': 2}, ['a', 'c']); // false
```
#### `Obj.hasAny()`
Returns `true` when any of the given keys resolves in the map:
``` dart
Obj.hasAny({'a': 1}, ['a', 'b']); // true
Obj.hasAny({'a': 1}, ['x', 'y']); // false
```
#### `Obj.mapKeys()`
Returns a new map with each key transformed by `fn`:
``` dart
Obj.mapKeys({'firstName': 'Anna'}, (k) => k.toLowerCase());
// {'firstname': 'Anna'}
```
#### `Obj.mapValues()`
Returns a new map with each value transformed by `fn`:
``` dart
Obj.mapValues({'a': 1, 'b': 2}, (v) => v * 10);
// {'a': 10, 'b': 20}
```
#### `Obj.merge()`
Recursively merges `source` into `target`. On key collision, `source` wins; nested maps are merged:
``` dart
Obj.merge(
{'a': {'x': 1}, 'b': 2},
{'a': {'y': 9}, 'b': 22},
);
// {'a': {'x': 1, 'y': 9}, 'b': 22}
```
#### `Obj.only()`
Returns a new map containing only the entries with the given keys:
``` dart
Obj.only({'name': 'Anna', 'role': 'admin', 'age': 30}, ['name', 'role']);
// {'name': 'Anna', 'role': 'admin'}
```
#### `Obj.prependKeysWith()`
Prefixes every top-level key in the map with the given prefix:
``` dart
Obj.prependKeysWith({'name': 'Anna', 'age': 30}, 'user_');
// {'user_name': 'Anna', 'user_age': 30}
```
#### `Obj.pull()`
Returns the value at `key` and removes it from the map:
``` dart
final user = {'name': 'Anna', 'temp': 'token'};
final temp = Obj.pull(user, 'temp'); // 'token'
// user: {'name': 'Anna'}
```
#### `Obj.query()`
Encodes a map as a URL query string:
``` dart
Obj.query({'name': 'Anna', 'tags': ['a', 'b']});
// 'name=Anna&tags%5B0%5D=a&tags%5B1%5D=b'
Obj.query({'filter': {'role': 'admin'}});
// 'filter%5Brole%5D=admin'
```
#### `Obj.set()`
Sets a value at `key`, creating nested maps along the path. Mutates the map in place and returns it for chaining:
``` dart
final user = {};
Obj.set(user, 'profile.email', 'a@b');
// user: {'profile': {'email': 'a@b'}}
```
#### `Obj.undot()`
Inflates a dot-keyed map back into a nested structure (the inverse of [`dot`](#method-obj-dot)):
``` dart
Obj.undot({'a.b': 1, 'a.c': 2});
// {'a': {'b': 1, 'c': 2}}
```
#### `Obj.whereNotEmpty()`
Returns a new map with entries whose values are `null` or empty (empty `String`, `Iterable`, or `Map`) removed:
``` dart
Obj.whereNotEmpty({'name': 'Anna', 'tags': [], 'bio': ''});
// {'name': 'Anna'}
```
#### `Obj.whereNotNull()`
Returns a new map with entries whose values are `null` removed:
``` dart
Obj.whereNotNull({'name': 'Anna', 'email': null});
// {'name': 'Anna'}
```
## Miscellaneous
These global functions live in `helper.dart` and are available wherever you import `nylo_framework`.
#### `api()`
Convenience helper for sending API requests through an `NyApiService`. See the [Networking](/docs/7.x/networking) page for full options:
``` dart
await api((request) =>
request.get('https://jsonplaceholder.typicode.com/posts'));
```
#### `dataToModel()`
Converts raw data (typically a JSON `Map`) into a model registered in `config/decoders.dart`. The type parameter is required:
``` dart
final user = dataToModel(data: {'name': 'Anna', 'age': 30});
```
#### `dump()`
Dumps a value to the console. Honors the app's `APP_DEBUG` flag unless `alwaysPrint: true`:
``` dart
dump('Hello World');
dump(user, tag: 'current user');
dump(payload, alwaysPrint: true);
```
#### `event()`
Fires an event of the given type using `Nylo.events()`. See [Events](/docs/7.x/events) for full usage:
``` dart
await event(data: {'user': 'Anna'});
```
#### `getAsset()`
Returns the full path for an asset in the `/assets` directory:
``` dart
final path = getAsset('videos/welcome.mp4');
// 'assets/videos/welcome.mp4'
```
#### `getEnv()`
Returns a value from your generated env (`env.g.dart`). Returns the default when the key is not set:
``` dart
final apiUrl = getEnv('API_URL');
final debug = getEnv('APP_DEBUG', defaultValue: false);
```
#### `getImageAsset()`
Returns the full path for an image in `/assets/images/`:
``` dart
Image.asset(getImageAsset('logo.png'));
```
#### `loadJson()`
Loads a JSON file from your assets bundle. Results are cached by default:
``` dart
final config = await loadJson>('config/app.json');
```
#### `match()`
Matches a value against a `Map` of cases and returns the corresponding value. Throws when no case matches and no `defaultValue` is provided:
``` dart
final color = match(
status,
() => {
'active': 'green',
'inactive': 'red',
'pending': 'orange',
},
defaultValue: 'grey',
);
```
> **Note:** This is a `Map`-based value lookup — distinct from [`Str.match`](#method-str-match), which performs regex matching.
#### `now()`
Returns the current `DateTime`:
``` dart
final timestamp = now();
```
#### `nyHexColor()`
Converts a hex color string to a `Color`. Accepts 6- or 8-digit values, with or without a leading `#`:
``` dart
final brand = nyHexColor('#FF6B35');
final translucent = nyHexColor('80FF6B35'); // 8-digit (alpha first)
```
#### `printDebug()`, `printError()`, `printInfo()`, `printWarning()`, `printSuccess()`, `printVerbose()`, `printAlert()`, `printEmergency()`
Severity-tagged console loggers. See the [Logging](/docs/7.x/logging) page for output formatting and the `alwaysPrint` flag:
``` dart
printInfo('User signed in');
printError('Payment failed', context: {'order_id': 42});
printDebug({'state': state});
```
#### `setBadgeNumber()`, `clearBadgeNumber()`
Sets or clears the app icon badge count. See [Local Notifications](/docs/7.x/local-notifications) for platform setup details:
``` dart
await setBadgeNumber(3);
await clearBadgeNumber();
```
#### `showNextLog()`
Forces the next `NyLogger` log to display even when `APP_DEBUG` is `false`. Useful for one-off diagnostics in release builds:
``` dart
showNextLog();
NyLogger.info('This will print regardless of APP_DEBUG');
```
#### `sleep()`
Delays execution for the given duration. The first argument is seconds; an optional second argument adds microseconds:
``` dart
await sleep(2); // 2 seconds
await sleep(0, 500_000); // 500 milliseconds
```
#### `trans()`
Returns a translated string by key. See [Localization](/docs/7.x/localization) for setup:
``` dart
final greeting = trans('home.welcome');
final personalized = trans('home.hello', arguments: {'name': 'Anna'});
```