HashMap API Reference

Constructors

empty

Since v2.0.0

Creates a new HashMap.

Signature

declare const empty: <K = never, V = never>() => HashMap<K, V>

fromIterable

Since v2.0.0

Creates a new HashMap from an iterable collection of key/value pairs.

Signature

declare const fromIterable: <K, V>(entries: Iterable<readonly [K, V]>) => HashMap<K, V>

make

Since v2.0.0

Constructs a new HashMap from an array of key/value pairs.

Signature

declare const make: <Entries extends ReadonlyArray<readonly [any, any]>>(...entries: Entries) => HashMap<Entries[number] extends readonly [infer K, any] ? K : never, Entries[number] extends readonly [any, infer V] ? V : never>

Elements

every

Since v3.14.0

Checks if all entries in a hashmap meets a specific condition.

Signature

declare const every: {
  <K, A>(predicate: (a: NoInfer<A>, k: K) => boolean): (self: HashMap<K, A>) => boolean;
  <K, A>(self: HashMap<K, A>, predicate: (a: A, k: K) => boolean): boolean;
}

findFirst

Since v2.0.0

Returns the first element that satisfies the specified predicate, or None if no such element exists.

Signature

declare const findFirst: {
  <K, A, B>(predicate: (a: NoInfer<A>, k: K) => a is B): (self: HashMap<K, A>) => Option<[K, B]>;
  <K, A>(predicate: (a: NoInfer<A>, k: K) => boolean): (self: HashMap<K, A>) => Option<[K, A]>;
  <K, A, B>(self: HashMap<K, A>, predicate: (a: A, k: K) => a is B): Option<[K, B]>;
  <K, A>(self: HashMap<K, A>, predicate: (a: A, k: K) => boolean): Option<[K, A]>;
}

get

Since v2.0.0

Safely lookup the value for the specified key in the HashMap using the internal hashing function.

Signature

declare const get: {
  <K1, K>(key: K1): <V>(self: HashMap<K, V>) => Option<V>;
  <K1, K, V>(self: HashMap<K, V>, key: K1): Option<V>;
}

getHash

Since v2.0.0

Lookup the value for the specified key in the HashMap using a custom hash.

Signature

declare const getHash: {
  <K1, K>(key: K1, hash: number): <V>(self: HashMap<K, V>) => Option<V>;
  <K1, K, V>(self: HashMap<K, V>, key: K1, hash: number): Option<V>;
}

has

Since v2.0.0

Checks if the specified key has an entry in the HashMap.

Signature

declare const has: {
  <K1, K>(key: K1): <K, V>(self: HashMap<K, V>) => boolean;
  <K1, K, V>(self: HashMap<K, V>, key: K1): boolean;
}

hasBy

Since v3.16.0

Checks if an element matching the given predicate exists in the given HashMap.

Signature

declare const hasBy: {
  <K, V>(predicate: (value: NoInfer<V>, key: NoInfer<K>) => boolean): (self: HashMap<K, V>) => boolean;
  <K, V>(self: HashMap<K, V>, predicate: (value: NoInfer<V>, key: NoInfer<K>) => boolean): boolean;
}

Example

import { HashMap } from "effect"

const hm = HashMap.make([1, 'a'])
HashMap.hasBy(hm, (value, key) => value === 'a' && key === 1); // -> true
HashMap.hasBy(hm, (value) => value === 'b'); // -> false

hasHash

Since v2.0.0

Checks if the specified key has an entry in the HashMap using a custom hash.

Signature

declare const hasHash: {
  <K1, K>(key: K1, hash: number): <V>(self: HashMap<K, V>) => boolean;
  <K1, K, V>(self: HashMap<K, V>, key: K1, hash: number): boolean;
}

isEmpty

Since v2.0.0

Checks if the HashMap contains any entries.

Signature

declare const isEmpty: <K, V>(self: HashMap<K, V>) => boolean

some

Since v3.13.0

Checks if any entry in a hashmap meets a specific condition.

Signature

declare const some: {
  <K, A>(predicate: (a: NoInfer<A>, k: K) => boolean): (self: HashMap<K, A>) => boolean;
  <K, A>(self: HashMap<K, A>, predicate: (a: A, k: K) => boolean): boolean;
}

Filtering

compact

Since v2.0.0

Filters out None values from a HashMap of Optionss.

Signature

declare const compact: <K, A>(self: HashMap<K, Option<A>>) => HashMap<K, A>

filter

Since v2.0.0

Filters entries out of a HashMap using the specified predicate.

Signature

declare const filter: {
  <K, A, B>(f: (a: NoInfer<A>, k: K) => a is B): (self: HashMap<K, A>) => HashMap<K, B>;
  <K, A>(f: (a: NoInfer<A>, k: K) => boolean): (self: HashMap<K, A>) => HashMap<K, A>;
  <K, A, B>(self: HashMap<K, A>, f: (a: A, k: K) => a is B): HashMap<K, B>;
  <K, A>(self: HashMap<K, A>, f: (a: A, k: K) => boolean): HashMap<K, A>;
}

filterMap

Since v2.0.0

Maps over the entries of the HashMap using the specified partial function and filters out None values.

Signature

declare const filterMap: {
  <A, K, B>(f: (value: A, key: K) => Option<B>): (self: HashMap<K, A>) => HashMap<K, B>;
  <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => Option<B>): HashMap<K, B>;
}

Folding

countBy

Since v3.17.0

Counts all the element of the given HashMap that pass the given predicate

Signature

declare const countBy: {
  <K, V>(predicate: (value: NoInfer<V>, key: NoInfer<K>) => boolean): (self: HashMap<K, V>) => number;
  <K, V>(self: HashMap<K, V>, predicate: (value: NoInfer<V>, key: NoInfer<K>) => boolean): number;
}

Example

import { HashMap } from "effect"

const map = HashMap.make([1, "a"], [2, "b"], [3, "c"])
const result = HashMap.countBy(map, (_v, key) => key % 2 === 1)
console.log(result) // 2

reduce

Since v2.0.0

Reduces the specified state over the entries of the HashMap.

Signature

declare const reduce: {
  <Z, V, K>(zero: Z, f: (accumulator: Z, value: V, key: K) => Z): (self: HashMap<K, V>) => Z;
  <K, V, Z>(self: HashMap<K, V>, zero: Z, f: (accumulator: Z, value: V, key: K) => Z): Z;
}

Getter

keySet

Since v2.0.0

Returns a HashSet of keys within the HashMap.

Signature

declare const keySet: <K, V>(self: HashMap<K, V>) => HashSet<K>

Getters

entries

Since v2.0.0

Returns an IterableIterator of the entries within the HashMap.

Signature

declare const entries: <K, V>(self: HashMap<K, V>) => IterableIterator<[K, V]>

keys

Since v2.0.0

Returns an IterableIterator of the keys within the HashMap.

Signature

declare const keys: <K, V>(self: HashMap<K, V>) => IterableIterator<K>

size

Since v2.0.0

Returns the number of entries within the HashMap.

Signature

declare const size: <K, V>(self: HashMap<K, V>) => number

toEntries

Since v2.0.0

Returns an Array<[K, V]> of the entries within the HashMap.

Signature

declare function toEntries<K, V>(self: HashMap<K, V>): Array<[K, V]>

toValues

Since v3.13.0

Returns an Array of the values within the HashMap.

Signature

declare function toValues<K, V>(self: HashMap<K, V>): Array<V>

values

Since v2.0.0

Returns an IterableIterator of the values within the HashMap.

Signature

declare const values: <K, V>(self: HashMap<K, V>) => IterableIterator<V>

Mapping

map

Since v2.0.0

Maps over the entries of the HashMap using the specified function.

Signature

declare const map: {
  <A, V, K>(f: (value: V, key: K) => A): (self: HashMap<K, V>) => HashMap<K, A>;
  <K, V, A>(self: HashMap<K, V>, f: (value: V, key: K) => A): HashMap<K, A>;
}

Models

HashMap

interface

Since v2.0.0

Signature

interface HashMap<out Key, out Value> extends Iterable<[Key, Value]>, Equal, Pipeable, Inspectable {
  readonly [TypeId]: typeof TypeId;
}

Other

beginMutation

Since v2.0.0

Marks the HashMap as mutable.

Signature

declare const beginMutation: <K, V>(self: HashMap<K, V>) => HashMap<K, V>

endMutation

Since v2.0.0

Marks the HashMap as immutable.

Signature

declare const endMutation: <K, V>(self: HashMap<K, V>) => HashMap<K, V>

HashMap

Since v2.0.0

modify

Since v2.0.0

Updates the value of the specified key within the HashMap if it exists.

Signature

declare const modify: {
  <K, V>(key: K, f: (v: V) => V): (self: HashMap<K, V>) => HashMap<K, V>;
  <K, V>(self: HashMap<K, V>, key: K, f: (v: V) => V): HashMap<K, V>;
}

modifyAt

Since v2.0.0

Set or remove the specified key in the HashMap using the specified update function. The value of the specified key will be computed using the provided hash.

The update function will be invoked with the current value of the key if it exists, or None if no such value exists.

Signature

declare const modifyAt: {
  <K, V>(key: K, f: UpdateFn<V>): (self: HashMap<K, V>) => HashMap<K, V>;
  <K, V>(self: HashMap<K, V>, key: K, f: UpdateFn<V>): HashMap<K, V>;
}

modifyHash

Since v2.0.0

Alter the value of the specified key in the HashMap using the specified update function. The value of the specified key will be computed using the provided hash.

The update function will be invoked with the current value of the key if it exists, or None if no such value exists.

This function will always either update or insert a value into the HashMap.

Signature

declare const modifyHash: {
  <K, V>(key: K, hash: number, f: UpdateFn<V>): (self: HashMap<K, V>) => HashMap<K, V>;
  <K, V>(self: HashMap<K, V>, key: K, hash: number, f: UpdateFn<V>): HashMap<K, V>;
}

mutate

Since v2.0.0

Mutates the HashMap within the context of the provided function.

Signature

declare const mutate: {
  <K, V>(f: (self: HashMap<K, V>) => void): (self: HashMap<K, V>) => HashMap<K, V>;
  <K, V>(self: HashMap<K, V>, f: (self: HashMap<K, V>) => void): HashMap<K, V>;
}

remove

Since v2.0.0

Remove the entry for the specified key in the HashMap using the internal hashing function.

Signature

declare const remove: {
  <K>(key: K): <V>(self: HashMap<K, V>) => HashMap<K, V>;
  <K, V>(self: HashMap<K, V>, key: K): HashMap<K, V>;
}

removeMany

Since v2.0.0

Removes all entries in the HashMap which have the specified keys.

Signature

declare const removeMany: {
  <K>(keys: Iterable<K>): <V>(self: HashMap<K, V>) => HashMap<K, V>;
  <K, V>(self: HashMap<K, V>, keys: Iterable<K>): HashMap<K, V>;
}

set

Since v2.0.0

Sets the specified key to the specified value using the internal hashing function.

Signature

declare const set: {
  <K, V>(key: K, value: V): (self: HashMap<K, V>) => HashMap<K, V>;
  <K, V>(self: HashMap<K, V>, key: K, value: V): HashMap<K, V>;
}

union

Since v2.0.0

Performs a union of this HashMap and that HashMap.

Signature

declare const union: {
  <K1, V1>(that: HashMap<K1, V1>): <K0, V0>(self: HashMap<K0, V0>) => HashMap<K1 | K0, V1 | V0>;
  <K0, V0, K1, V1>(self: HashMap<K0, V0>, that: HashMap<K1, V1>): HashMap<K0 | K1, V0 | V1>;
}

Refinements

isHashMap

Since v2.0.0

Signature

declare const isHashMap: {
  <K, V>(u: Iterable<readonly [K, V]>): u is HashMap<K, V>;
  (u: unknown): u is HashMap<unknown, unknown>;
}

Sequencing

flatMap

Since v2.0.0

Chains over the entries of the HashMap using the specified function.

NOTE: the hash and equal of both maps have to be the same.

Signature

declare const flatMap: {
  <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>;
  <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>;
}

Symbol

TypeId

type

Since v2.0.0

Signature

type TypeId = typeof TypeId

Traversing

forEach

Since v2.0.0

Applies the specified function to the entries of the HashMap.

Signature

declare const forEach: {
  <V, K>(f: (value: V, key: K) => void): (self: HashMap<K, V>) => void;
  <V, K>(self: HashMap<K, V>, f: (value: V, key: K) => void): void;
}

Unsafe

unsafeGet

Since v2.0.0

Unsafely lookup the value for the specified key in the HashMap using the internal hashing function.

Signature

declare const unsafeGet: {
  <K1, K>(key: K1): <V>(self: HashMap<K, V>) => V;
  <K1, K, V>(self: HashMap<K, V>, key: K1): V;
}