<K, V>(self: HashMap<K, V>): Array<[K, V]>Returns an Array<[K, V]> of the entries within the HashMap.
Example (Converting entries to an array)
import { HashMap } from "effect"
const gameScores = HashMap.make(
["alice", 1250],
["bob", 980],
["charlie", 1100]
)
// Convert to entries for processing
const scoreEntries = HashMap.toEntries(gameScores)
// Sort by score (descending)
const leaderboard = scoreEntries
.sort(([, a], [, b]) => b - a)
.map(([player, score], rank) => `${rank + 1}. ${player}: ${score}`)
console.log(leaderboard)
// ["1. alice: 1250", "2. charlie: 1100", "3. bob: 980"]
// Convert back to HashMap if needed
const sortedMap = HashMap.fromIterable(scoreEntries)getters
Source effect/HashMap.ts:6611 lines
export const const toEntries: <K, V>(
self: HashMap<K, V>
) => Array<[K, V]>
Returns an Array<[K, V]> of the entries within the HashMap.
Example (Converting entries to an array)
import { HashMap } from "effect"
const gameScores = HashMap.make(
["alice", 1250],
["bob", 980],
["charlie", 1100]
)
// Convert to entries for processing
const scoreEntries = HashMap.toEntries(gameScores)
// Sort by score (descending)
const leaderboard = scoreEntries
.sort(([, a], [, b]) => b - a)
.map(([player, score], rank) => `${rank + 1}. ${player}: ${score}`)
console.log(leaderboard)
// ["1. alice: 1250", "2. charlie: 1100", "3. bob: 980"]
// Convert back to HashMap if needed
const sortedMap = HashMap.fromIterable(scoreEntries)
toEntries = <function (type parameter) K in <K, V>(self: HashMap<K, V>): Array<[K, V]>K, function (type parameter) V in <K, V>(self: HashMap<K, V>): Array<[K, V]>V>(self: HashMap<K, V>(parameter) self: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
interface HashMap<out Key, out Value>A HashMap is an immutable key-value data structure that provides efficient lookup,
insertion, and deletion operations. It uses a Hash Array Mapped Trie (HAMT) internally
for structural sharing and optimal performance.
Example (Using basic HashMap operations)
import { HashMap } from "effect"
// Create a HashMap
const map = HashMap.make(["a", 1], ["b", 2], ["c", 3])
// Access values
const valueA = HashMap.get(map, "a") // Option.some(1)
const valueD = HashMap.get(map, "d") // Option.none()
// Check if key exists
console.log(HashMap.has(map, "b")) // true
// Add/update values (returns new HashMap)
const updated = HashMap.set(map, "d", 4)
console.log(HashMap.size(updated)) // 4
The HashMap namespace contains type-level utilities and helper types
for working with HashMap instances.
Example (Extracting HashMap types)
import { HashMap } from "effect"
// Create a concrete HashMap for type extraction
const inventory = HashMap.make(
["laptop", { quantity: 5, price: 999 }],
["mouse", { quantity: 20, price: 29 }]
)
// Extract types for reuse
type ProductId = HashMap.HashMap.Key<typeof inventory> // string
type Product = HashMap.HashMap.Value<typeof inventory> // { quantity: number, price: number }
type InventoryEntry = HashMap.HashMap.Entry<typeof inventory> // [string, Product]
// Use extracted types in functions
const updateInventory = (id: ProductId, product: Product) =>
HashMap.set(inventory, id, product)
const processEntry = ([id, product]: InventoryEntry) =>
`${id}: ${product.quantity} @ $${product.price}`
// Example of extracted types in action
const newProduct: Product = { quantity: 10, price: 199 }
const updatedInventory = updateInventory("tablet", newProduct)
HashMap<function (type parameter) K in <K, V>(self: HashMap<K, V>): Array<[K, V]>K, function (type parameter) V in <K, V>(self: HashMap<K, V>): Array<[K, V]>V>): interface Array<T>Array<[function (type parameter) K in <K, V>(self: HashMap<K, V>): Array<[K, V]>K, function (type parameter) V in <K, V>(self: HashMap<K, V>): Array<[K, V]>V]> => var Array: ArrayConstructorArray.ArrayConstructor.from<[K, V]>(iterable: Iterable<[K, V]> | ArrayLike<[K, V]>): [K, V][] (+3 overloads)Creates an array from an iterable object.
from(const entries: <K, V>(
self: HashMap<K, V>
) => IterableIterator<[K, V]>
Returns an IterableIterator of the entries within the HashMap.
Example (Iterating entries)
import { HashMap } from "effect"
// Create a configuration map
const config = HashMap.make(
["database.host", "localhost"],
["database.port", "5432"],
["cache.enabled", "true"]
)
// Sort the derived array for deterministic output
const settings = Array.from(HashMap.entries(config))
.sort(([left], [right]) => left.localeCompare(right))
.map(([key, value]) => `Setting ${key} = ${value}`)
console.log(settings)
// ["Setting cache.enabled = true", "Setting database.host = localhost", "Setting database.port = 5432"]
// Convert to array when you need all entries at once
const allEntries = Array.from(HashMap.entries(config))
console.log(allEntries.length) // 3
entries(self: HashMap<K, V>(parameter) self: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
Referenced by 4 symbols