<K1 extends K, K>(key: K1): <K, V>(self: HashMap<K, V>) => boolean
<K1 extends K, K, V>(self: HashMap<K, V>, key: K1): booleanChecks whether the specified key has an entry in the HashMap.
Example (Checking for keys)
import { HashMap } from "effect"
const map = HashMap.make(["a", 1], ["b", 2])
console.log(HashMap.has(map, "a")) // true
console.log(HashMap.has(map, "c")) // false
// Using pipe syntax
const hasB = HashMap.has("b")(map)
console.log(hasB) // trueelements
Source effect/HashMap.ts:4404 lines
export const const has: {
<K1 extends K, K>(key: K1): <K, V>(
self: HashMap<K, V>
) => boolean
<K1 extends K, K, V>(
self: HashMap<K, V>,
key: K1
): boolean
}
Checks whether the specified key has an entry in the HashMap.
Example (Checking for keys)
import { HashMap } from "effect"
const map = HashMap.make(["a", 1], ["b", 2])
console.log(HashMap.has(map, "a")) // true
console.log(HashMap.has(map, "c")) // false
// Using pipe syntax
const hasB = HashMap.has("b")(map)
console.log(hasB) // true
has: {
<function (type parameter) K1 in <K1 extends K, K>(key: K1): <K, V>(self: HashMap<K, V>) => booleanK1 extends function (type parameter) K in <K1 extends K, K>(key: K1): <K, V>(self: HashMap<K, V>) => booleanK, function (type parameter) K in <K1 extends K, K>(key: K1): <K, V>(self: HashMap<K, V>) => booleanK>(key: K1 extends Kkey: function (type parameter) K1 in <K1 extends K, K>(key: K1): <K, V>(self: HashMap<K, V>) => booleanK1): <function (type parameter) K in <K, V>(self: HashMap<K, V>): booleanK, function (type parameter) V in <K, V>(self: HashMap<K, V>): booleanV>(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>): booleanK, function (type parameter) V in <K, V>(self: HashMap<K, V>): booleanV>) => boolean
<function (type parameter) K1 in <K1 extends K, K, V>(self: HashMap<K, V>, key: K1): booleanK1 extends function (type parameter) K in <K1 extends K, K, V>(self: HashMap<K, V>, key: K1): booleanK, function (type parameter) K in <K1 extends K, K, V>(self: HashMap<K, V>, key: K1): booleanK, function (type parameter) V in <K1 extends K, K, V>(self: HashMap<K, V>, key: K1): booleanV>(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 <K1 extends K, K, V>(self: HashMap<K, V>, key: K1): booleanK, function (type parameter) V in <K1 extends K, K, V>(self: HashMap<K, V>, key: K1): booleanV>, key: K1 extends Kkey: function (type parameter) K1 in <K1 extends K, K, V>(self: HashMap<K, V>, key: K1): booleanK1): boolean
} = import internalinternal.const has: anyhasReferenced by 2 symbols