underscore library

Functions

add(num augend, num addend) → num

Adds two numbers.

camelCase(String input) → String

Converts a given string to camel case format.

capitalize([String input = '']) → String

Converts the first character of the given string to uppercase and the remaining characters to lowercase.

ceil(num number, [int precision = 0]) → num

Computes number rounded up to precision.

chunk<T>(List<T> array, [int size = 1]) → List<List<T>>

Creates a new list of chunks of the given array, each chunk containing size number of elements. If the array cannot be evenly divided into chunks of size size, the final chunk will contain the remaining elements.

clamp(num number, num lower, num upper) → num

Clamps number within the inclusive lower and upper bounds.

compact<T>(List<T> array) → List<T>

Returns a new list with all null, empty, false, or NaN elements removed from the input list.

concat<T>(List<T> array, List values) → List<T>

Concatenates a given list array with one or more dynamic values.

difference<T>(List<T> array, [List<T>? values]) → List<T>

Returns a new list containing the elements from the original list array that are not present in the optional values list.

divide(num dividend, num divisor) → num

Divide two numbers.

drop<T>(List<T> array, [int n = 1]) → List<T>

Creates a slice of array with n elements dropped from the beginning.

dropRight<T>(List<T> array, [int n = 1]) → List<T>

Creates a slice of array with n elements dropped from the end.

endsWith(String string, String target, [int? position]) → bool

Checks if the given string ends with the specified target string.

fill<T>(List<T> array, dynamic value, [int start = 0, int? end]) → List<T>

Fills elements of a List with a specified value within a given range.

filter(List collection, [Function? predicate]) → List

Returns a new list containing elements of the collection for which the predicate function returns true.

findIndex<T>(List<T> array, [Predicate<T>? predicate, int fromIndex = 0]) → int

Returns the index of the first element in the list that satisfies the provided predicate function. If no such element is found, returns -1.

findLastIndex(List array, [bool predicate(dynamic)?, int fromIndex = -1]) → int

Returns the index of the last element in the array for which the predicate function returns true. If no such element is found, returns -1.

get(Map<String, dynamic> map, String path, [dynamic defaultValue]) → dynamic

Retrieves a value from a nested Map or List structure based on a given path. If the path does not exist, it returns the provided defaultValue.

getJsonValue(dynamic json, String path, dynamic defaultValue) → Future

Retrieves a value from a nested JSON structure based on a provided path.

groupBy(Iterable collection, [dynamic iteratee]) → Map<dynamic, List>

Groups the elements of an Iterable collection based on a specified iteratee.

indexOf<T>(List<T> array, T value, [int fromIndex = 0]) → int

Gets the index at which the first occurrence of value is found in the array using SameValueZero for equality comparisons. If fromIndex is negative, it's used as the offset from the end of the array.

inRange(num number, [num start = 0, num? end]) → bool

Checks if number is between start and up to, but not including, end.

isEqual(dynamic value, dynamic other) → bool

Performs a deep comparison between two values to determine if they are equivalent.

isInteger(dynamic value) → bool

Checks if value is an integer.

isNullOrBlank(dynamic val) → bool

join(List array, dynamic takeVal) → String

Joins the elements of an array into a single string using the specified separator.

keys(dynamic object) → List<String>

last(List list) → dynamic

Gets the last element of a list.

matches(Map<String, dynamic> source) → Predicate<Map<String, dynamic>>

Returns a predicate function that checks whether a given map matches the provided source map.

matchesProperty<T>(List property) → Predicate<T>

Creates a predicate function that checks if a given property of an object matches a specified value.

parsePath(String path) → List

Parses the path string into a list of keys and indices.

property<T>(dynamic path) → PropertyAccessor<T>

Creates a property accessor function based on the provided path.

pull<T>(List<T> array, List<T> values) → List<T>

Removes all given values from the array using equality comparisons.

remove<T>(List<T> array, [bool predicate(T)?]) → List<T>

Removes all elements from the array for which the predicate returns true and returns a new list containing the removed elements.

removeAt<T>(List<T> list, int index) → List<T>

Removes the element at the specified index from the given List.

reverse<T>(List<T> array) → List<T>

Reverses the elements of the given array in place.

shuffle<T>(List<T> collection) → List<T>

Shuffles a list using the Fisher-Yates shuffle algorithm.

size(dynamic collection) → int

Returns the size of the given collection.

slice<T>(List<T> list, [int start = 0, int? end]) → List<T>

Creates a slice of a list from start up to, but not including, end.

some<T>(Iterable<T> collection, bool predicate(T value, int index, Iterable<T> collection)) → bool

Checks if predicate returns truthy for any element of collection. Iteration is stopped once predicate returns truthy. The predicate is invoked with three arguments: (value, index|key, collection).

sortBy(List<Map<String, dynamic>> collection, List iteratees) → List<Map<String, dynamic>>

Sorts a list of maps collection based on the provided list of iteratees.

toInteger(dynamic value) → int

Converts the given value to an integer.

toNumber(dynamic value) → double

Converts the given value to a number.

trim(String str, [String chars = ""]) → String

Removes leading and trailing whitespace or specified characters from str.

uniq<T>(List<T> array) → List<T>

Creates a duplicate-free version of an array, using SameValueZero for equality comparisons, in which only the first occurrence of each element is kept. The order of result values is determined by the order they occur in the array.

uniqBy<T, V>(List<T> array, V iteratee(T)) → List<T>

Returns a new array with unique elements, where uniqueness is determined by the result of invoking the provided iteratee function on each element.

values(dynamic object) → List

Returns a list containing all the values of the provided object's own properties.

words(String string, [RegExp? pattern]) → List<String?>

Splits the given string into an array of its words.

zip<T>(List<List<T>> arrays) → List<List<T?>>

Creates a list of grouped elements, where each group contains elements at the same index from the given arrays.

zipObject<K, V>(List<K> keys, List<V> values) → Map<K, V>

Creates a new map from the given keys and values arrays.

zipWith<R>(List<List> arrays, R iteratee(List)) → List<R>

Combines elements from multiple lists using a provided iteratee function. This function is similar to zip but accepts an iteratee to specify how grouped values should be combined. The iteratee is invoked with the elements of each group: (...group).

Typedefs

PropertyAccessor<T> = dynamic Function(T object)

A function type for accessing properties of objects of type T.