class Collection

extends

Map
export declare class Collection<K, V> extends Map<K, V>

A Map with additional utility methods. This is used throughout discord.js rather than Arrays for anything that has an ID, for significantly improved performance and ease-of-use.

Type Parameters

K

V

at(
index: number
) : V | undefined

Identical to Array.at(). Returns the item at a given index, allowing for positive and negative integers. Negative integers count back from the last item in the collection.

clone() : Collection<K, V>

Creates an identical shallow copy of this collection.

Examples:const newColl = someColl.clone();

static
combineEntries<

K

V

>(
entries: Iterable<[ K, V ]>
combine: (firstValue: V, secondValue: V, key: K) => V
) : Collection<K, V>

Creates a Collection from a list of entries.

Examples:Collection.combineEntries([["a", 1], ["b", 2], ["a", 2]], (x, y) = x + y); // returns Collection "a" = 3, "b" = 2

concat(
collections: ReadonlyCollection<K, V>[]
) : Collection<K, V>

Combines this collection with others into a new collection. None of the source collections are modified.

Examples:const newColl = someColl.concat(someOtherColl, anotherColl, ohBoyAColl);

difference<

T

>(
other: ReadonlyCollection<K, T>
) : Collection<K, V | T>

The difference method returns a new structure containing items where the key is present in one of the original structures but not the other.

each(
fn: (value: V, key: K, collection: this) => void
) : this

Identical to Map.forEach(), but returns the collection instead of undefined.

Examples:collection .each(user = console.log(user.username)) .filter(user = user.bot) .each(user = console.log(user.username));

ensure(
key: K
defaultValueGenerator: (key: K, collection: this) => V
) : V

Obtains the value of the given key if it exists, otherwise sets and returns the value provided by the default value generator.

Examples:collection.ensure(guildId, () = defaultGuildConfig);

equals(
collection: ReadonlyCollection<K, V>
) : boolean

Checks if this collection shares identical items with another. This is different to checking for equality using equal-signs, because the collections may be different objects, but contain the same data.

Returns: Whether the collections have identical contents

every<

K2 extends K

>(
fn: (value: V, key: K, collection: this) => key is K2
) : this is Collection<K2, V>

Checks if all items passes a test. Identical in behavior to Array.every().

Examples:collection.every(user = !user.bot);

filter<

K2 extends K

>(
fn: (value: V, key: K, collection: this) => key is K2
) : Collection<K2, V>

Identical to Array.filter(), but returns a Collection instead of an Array.

Examples:collection.filter(user = user.username === 'Bob');

find<

V2 extends V

>(
fn: (value: V, key: K, collection: this) => value is V2
) : V2 | undefined

Searches for a single item where the given function returns a truthy value. This behaves like Array.find(). All collections used in Discord.js are mapped using their id property, and if you want to find by id you should use the get method. See MDN for details.

Examples:collection.find(user = user.username === 'Bob');

findKey<

K2 extends K

>(
fn: (value: V, key: K, collection: this) => key is K2
) : K2 | undefined

Searches for the key of a single item where the given function returns a truthy value. This behaves like Array.findIndex(), but returns the key rather than the positional index.

Examples:collection.findKey(user = user.username === 'Bob');

first() : V | undefined

Obtains the first value(s) in this collection.

Returns: A single value if no amount is provided or an array of values, starting from the end if amount is negative

firstKey() : K | undefined

Obtains the first key(s) in this collection.

Returns: A single key if no amount is provided or an array of keys, starting from the end if amount is negative

flatMap<

T

>(
fn: (value: V, key: K, collection: this) => Collection<K, T>
) : Collection<K, T>

Maps each item into a Collection, then joins the results into a single Collection. Identical in behavior to Array.flatMap().

Examples:collection.flatMap(guild = guild.members.cache);

hasAll(
keys: K[]
) : boolean

Checks if all of the elements exist in the collection.

Returns: true if all of the elements exist, false if at least one does not exist.

hasAny(
keys: K[]
) : boolean

Checks if any of the elements exist in the collection.

Returns: true if any of the elements exist, false if none exist.

intersect<

T

>(
other: ReadonlyCollection<K, T>
) : Collection<K, T>

The intersect method returns a new structure containing items where the keys and values are present in both original structures.

keyAt(
index: number
) : K | undefined

Identical to Array.at(). Returns the key at a given index, allowing for positive and negative integers. Negative integers count back from the last item in the collection.

last() : V | undefined

Obtains the last value(s) in this collection.

Returns: A single value if no amount is provided or an array of values, starting from the start if amount is negative

lastKey() : K | undefined

Obtains the last key(s) in this collection.

Returns: A single key if no amount is provided or an array of keys, starting from the start if amount is negative

map<

T

>(
fn: (value: V, key: K, collection: this) => T
) : T[]

Maps each item to another value into an array. Identical in behavior to Array.map().

Examples:collection.map(user = user.tag);

mapValues<

T

>(
fn: (value: V, key: K, collection: this) => T
) : Collection<K, T>

Maps each item to another value into a collection. Identical in behavior to Array.map().

Examples:collection.mapValues(user = user.tag);

merge<

T

R

>(
other: ReadonlyCollection<K, T>
whenInSelf: (value: V, key: K) => Keep<R>
whenInOther: (valueOther: T, key: K) => Keep<R>
whenInBoth: (value: V, valueOther: T, key: K) => Keep<R>
) : Collection<K, R>

Merges two Collections together into a new Collection.

Examples:// Sums up the entries in two collections. coll.merge( other, x = ( keep: true, value: x ), y = ( keep: true, value: y ), (x, y) = ( keep: true, value: x + y ), );// Intersects two collections in a left-biased manner. coll.merge( other, x = ( keep: false ), y = ( keep: false ), (x, _) = ( keep: true, value: x ), );

partition<

K2 extends K

>(
fn: (value: V, key: K, collection: this) => key is K2
) : [ Collection<K2, V>, Collection<Exclude<K, K2>, V> ]

Partitions the collection into two collections where the first collection contains the items that passed and the second contains the items that failed.

Examples:const [big, small] = collection.partition(guild = guild.memberCount 250);

random() : V | undefined

Obtains unique random value(s) from this collection.

Returns: A single value if no amount is provided or an array of values

randomKey() : K | undefined

Obtains unique random key(s) from this collection.

Returns: A single key if no amount is provided or an array

reduce<

T

>(
fn: (accumulator: T, value: V, key: K, collection: this) => T
initialValue?: T
) : T

Applies a function to produce a single value. Identical in behavior to Array.reduce().

Examples:collection.reduce((acc, guild) = acc + guild.memberCount, 0);

reverse() : this

Identical to Array.reverse() but returns a Collection instead of an Array.

some(
fn: (value: V, key: K, collection: this) => boolean
) : boolean

Checks if there exists an item that passes a test. Identical in behavior to Array.some().

Examples:collection.some(user = user.discriminator === '0000');

sort(
compareFunction?: Comparator<K, V>
) : this

The sort method sorts the items of a collection in place and returns it. The sort is not necessarily stable in Node 10 or older. The default sort order is according to string Unicode code points.

Examples:collection.sort((userA, userB) = userA.createdTimestamp - userB.createdTimestamp);

sorted(
compareFunction?: Comparator<K, V>
) : Collection<K, V>

The sorted method sorts the items of a collection and returns it. The sort is not necessarily stable in Node 10 or older. The default sort order is according to string Unicode code points.

Examples:collection.sorted((userA, userB) = userA.createdTimestamp - userB.createdTimestamp);

sweep(
fn: (value: V, key: K, collection: this) => boolean
) : number

Removes items that satisfy the provided filter function.

Returns: The number of removed entries

tap(
fn: (collection: this) => void
) : this

Runs a function on the collection and returns the collection.

Examples:collection .tap(coll = console.log(coll.size)) .filter(user = user.bot) .tap(coll = console.log(coll.size))

toJSON() : V[]