/collections/mod.ts | std@0.181.0

import * as mod from "https://dotland.deno.dev/std@0.181.0/collections/mod.ts";

Functions for specific common tasks around collection types like Array and Record. This module is heavily inspired by kotlins stdlib.

All provided functions are pure, which also means that they do not mutate your inputs, returning a new value instead.
All functions are importable on their own by referencing their snake_case named file (e.g. collections/sort_by.ts)

This module re-exports several modules, and importing this module directly will likely include a lot of code that you might not use.

Consider importing the function directly. For example to import groupBy import the module using the snake cased version of the module:

import { groupBy } from "https://deno.land/std@0.181.0/collections/group_by.ts";

Classes

BinaryHeap

A priority queue implemented with a binary heap. The heap is in descending order by default, using JavaScript's built-in comparison operators to sort the values.

Functions

f aggregateGroups	Applies the given aggregator to each group in the given grouping, returning the results together with the respective group keys
f ascend	Compares its two arguments for ascending order using JavaScript's built in comparison operators.
f associateBy	Transforms the given array into a Record, extracting the key of each element using the given selector. If the selector produces the same key for multiple elements, the latest one will be used (overriding the ones before it).
f associateWith	Builds a new Record using the given array as keys and choosing a value for each key using the given selector. If any of two pairs would have the same value the latest on will be used (overriding the ones before it).
f chunk	Splits the given array into chunks of the given size and returns them.
f deepMerge	Merges the two given Records, recursively merging any nested Records with the second collection overriding the first in case of conflict
f descend	Compares its two arguments for descending order using JavaScript's built in comparison operators.
f distinct	Returns all distinct elements in the given array, preserving order by first occurrence.
f distinctBy	Returns all elements in the given array that produce a distinct value using the given selector, preserving order by first occurrence.
f dropLastWhile	Returns a new array that drops all elements in the given collection until the last element that does not match the given predicate
f dropWhile	Returns a new array that drops all elements in the given collection until the first element that does not match the given predicate.
f filterEntries	Returns a new record with all entries of the given record except the ones that do not match the given predicate.
f filterKeys	Returns a new record with all entries of the given record except the ones that have a key that does not match the given predicate.
f filterValues	Returns a new record with all entries of the given record except the ones that have a value that does not match the given predicate.
f findSingle	Returns an element if and only if that element is the only one matching the given condition. Returns `undefined` otherwise.
f firstNotNullishOf	Applies the given selector to elements in the given array until a value is produced that is neither `null` nor `undefined` and returns that value. Returns `undefined` if no such value is produced.
f groupBy	Applies the given selector to each element in the given array, returning a Record containing the results as keys and all values that produced that key as values.
f includesValue	If the given value is part of the given object it returns true, otherwise it returns false. Doesn't work with non-primitive values: includesValue({x: {}}, {}) returns false.
f intersect	Returns all distinct elements that appear at least once in each of the given arrays.
f joinToString	Transforms the elements in the given array to strings using the given selector. Joins the produced strings into one using the given `separator` and applying the given `prefix` and `suffix` to the whole string afterwards. If the array could be huge, you can specify a non-negative value of `limit`, in which case only the first `limit` elements will be appended, followed by the `truncated` string. Returns the resulting string.
f mapEntries	Applies the given transformer to all entries in the given record and returns a new record containing the results.
f mapKeys	Applies the given transformer to all keys in the given record's entries and returns a new record containing the transformed entries.
f mapNotNullish	Returns a new array, containing all elements in the given array transformed using the given transformer, except the ones that were transformed to `null` or `undefined`.
f mapValues	Applies the given transformer to all values in the given record and returns a new record containing the resulting keys associated to the last value that produced them.
f maxBy	Returns the first element that is the largest value of the given function or undefined if there are no elements.
f maxOf	Applies the given selector to all elements of the provided collection and returns the max value of all elements. If an empty array is provided the function will return undefined
f maxWith	Returns the first element having the largest value according to the provided comparator or undefined if there are no elements.
f minBy	Returns the first element that is the smallest value of the given function or undefined if there are no elements
f minOf	Applies the given selector to all elements of the given collection and returns the min value of all elements. If an empty array is provided the function will return undefined.
f minWith	Returns the first element having the smallest value according to the provided comparator or undefined if there are no elements
f partition	Returns a tuple of two arrays with the first one containing all elements in the given array that match the given predicate and the second one containing all that do not.
f permutations	Builds all possible orders of all elements in the given array Ignores equality of elements, meaning this will always return the same number of permutations for a given length of input.
f reduceGroups	Applies the given reducer to each group in the given Grouping, returning the results together with the respective group keys.
f runningReduce	Calls the given reducer on each element of the given collection, passing its result as the accumulator to the next respective call, starting with the given initialValue. Returns all intermediate accumulator results.
f sample	Returns a random element from the given array
f slidingWindows	Generates sliding views of the given array of the given size and returns a new array containing all of them.
f sortBy	Returns all elements in the given collection, sorted by their result using the given selector. The selector function is called only once for each element.
f sumOf	Applies the given selector to all elements in the given collection and calculates the sum of the results.
f takeLastWhile	Returns all elements in the given array after the last element that does not match the given predicate.
f takeWhile	Returns all elements in the given collection until the first element that does not match the given predicate.
f union	Returns all distinct elements that appear in any of the given arrays
f unzip	Builds two separate arrays from the given array of 2-tuples, with the first returned array holding all first tuple elements and the second one holding all the second elements.
f withoutAll	Returns an array excluding all given values.
f zip

Type Aliases

T DeepMerge	Merge deeply two objects
T DeepMergeOptions	Deep merge options
T JoinToStringOptions	Options for joinToString
T MergingStrategy	Merging strategy