<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>Maps each entry to a HashMap and flattens the results.
Gotchas
The hash and equality behavior of both maps have to be the same.
Example (Flat mapping values)
import { HashMap } from "effect"
const map1 = HashMap.make(["a", 1], ["b", 2])
const map2 = HashMap.flatMap(
map1,
(value, key) => HashMap.make([key + "1", value], [key + "2", value * 2])
)
console.log(HashMap.size(map2)) // 4
console.log(HashMap.get(map2, "a1")) // Option.some(1)
console.log(HashMap.get(map2, "b2")) // Option.some(4)sequencing
Source effect/HashMap.ts:10404 lines
export const 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>
}
Maps each entry to a HashMap and flattens the results.
Gotchas
The hash and equality behavior of both maps have to be the same.
Example (Flat mapping values)
import { HashMap } from "effect"
const map1 = HashMap.make(["a", 1], ["b", 2])
const map2 = HashMap.flatMap(
map1,
(value, key) => HashMap.make([key + "1", value], [key + "2", value * 2])
)
console.log(HashMap.size(map2)) // 4
console.log(HashMap.get(map2, "a1")) // Option.some(1)
console.log(HashMap.get(map2, "b2")) // Option.some(4)
flatMap: {
<function (type parameter) A in <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>A, function (type parameter) K in <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>K, function (type parameter) B in <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>B>(f: (value: A, key: K) => HashMap<K, B>f: (value: Avalue: function (type parameter) A in <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>A, key: Kkey: function (type parameter) K in <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>K) => 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 <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>K, function (type parameter) B in <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>B>): (self: HashMap<K, A>(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 <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>K, function (type parameter) A in <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>A>) => 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 <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>K, function (type parameter) B in <A, K, B>(f: (value: A, key: K) => HashMap<K, B>): (self: HashMap<K, A>) => HashMap<K, B>B>
<function (type parameter) K in <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>K, function (type parameter) A in <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>A, function (type parameter) B in <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>B>(self: HashMap<K, A>(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, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>K, function (type parameter) A in <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>A>, f: (value: A, key: K) => HashMap<K, B>f: (value: Avalue: function (type parameter) A in <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>A, key: Kkey: function (type parameter) K in <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>K) => 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} @ $${product.price}`
// Example of extracted types in action
const newProduct: Product = { quantity: 10, price: 199 }
const updatedInventory = updateInventory("tablet", newProduct)
HashMap<function (type parameter) K in <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>K, function (type parameter) B in <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>B>): interface HashMap<out Key, out Value>A HashMap is an immutable key-value data structure that provides efficient lookup,
insertion, and deletion operations. It uses a Hash Array Mapped Trie (HAMT) internally
for structural sharing and optimal performance.
Example (Using basic HashMap operations)
import { HashMap } from "effect"
// Create a HashMap
const map = HashMap.make(["a", 1], ["b", 2], ["c", 3])
// Access values
const valueA = HashMap.get(map, "a") // Option.some(1)
const valueD = HashMap.get(map, "d") // Option.none()
// Check if key exists
console.log(HashMap.has(map, "b")) // true
// Add/update values (returns new HashMap)
const updated = HashMap.set(map, "d", 4)
console.log(HashMap.size(updated)) // 4
The HashMap namespace contains type-level utilities and helper types
for working with HashMap instances.
Example (Extracting HashMap types)
import { HashMap } from "effect"
// Create a concrete HashMap for type extraction
const inventory = HashMap.make(
["laptop", { quantity: 5, price: 999 }],
["mouse", { quantity: 20, price: 29 }]
)
// Extract types for reuse
type ProductId = HashMap.HashMap.Key<typeof inventory> // string
type Product = HashMap.HashMap.Value<typeof inventory> // { quantity: number, price: number }
type InventoryEntry = HashMap.HashMap.Entry<typeof inventory> // [string, Product]
// Use extracted types in functions
const updateInventory = (id: ProductId, product: Product) =>
HashMap.set(inventory, id, product)
const processEntry = ([id, product]: InventoryEntry) =>
`${id}: ${product.quantity} @ $${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, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>K, function (type parameter) B in <K, A, B>(self: HashMap<K, A>, f: (value: A, key: K) => HashMap<K, B>): HashMap<K, B>B>
} = import internalinternal.const flatMap: anyflatMap