(key: string): <V>(self: Trie<V>) => Option<[string, V]>
<V>(self: Trie<V>, key: string): Option<[string, V]>Returns the longest key/value in the Trie
that is a prefix of that key if it exists, None otherwise.
Example (Finding the longest prefix)
import { Trie } from "effect"
import * as assert from "node:assert"
const trie = Trie.empty<number>().pipe(
Trie.insert("shells", 0),
Trie.insert("sells", 1),
Trie.insert("she", 2)
)
const none = Trie.longestPrefixOf(trie, "sell")
const some = Trie.longestPrefixOf(trie, "sells")
assert.equal(none._tag, "None")
assert.equal(some._tag, "Some")
if (some._tag === "Some") {
assert.deepStrictEqual(some.value, ["sells", 1])
}getters
Source effect/Trie.ts:4394 lines
export const const longestPrefixOf: {
(key: string): <V>(
self: Trie<V>
) => Option<[string, V]>
<V>(self: Trie<V>, key: string): Option<
[string, V]
>
}
Returns the longest key/value in the Trie
that is a prefix of that key if it exists, None otherwise.
Example (Finding the longest prefix)
import { Trie } from "effect"
import * as assert from "node:assert"
const trie = Trie.empty<number>().pipe(
Trie.insert("shells", 0),
Trie.insert("sells", 1),
Trie.insert("she", 2)
)
const none = Trie.longestPrefixOf(trie, "sell")
const some = Trie.longestPrefixOf(trie, "sells")
assert.equal(none._tag, "None")
assert.equal(some._tag, "Some")
if (some._tag === "Some") {
assert.deepStrictEqual(some.value, ["sells", 1])
}
longestPrefixOf: {
(key: stringkey: string): <function (type parameter) V in <V>(self: Trie<V>): Option<[string, V]>V>(self: Trie<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 Trie<in out Value>An immutable string-keyed map optimized for prefix lookup. Iteration yields
[key, value] pairs in key order, and update operations such as insert and
remove return new Trie values.
Example (Using a trie for prefix search)
import { Trie } from "effect"
// Create a trie with string-to-number mappings
const trie: Trie.Trie<number> = Trie.make(
["apple", 1],
["app", 2],
["application", 3],
["banana", 4]
)
// Get values by exact key
console.log(Trie.get(trie, "apple")) // Some(1)
console.log(Trie.get(trie, "grape")) // None
// Find all keys with a prefix
console.log(Array.from(Trie.keysWithPrefix(trie, "app")))
// ["app", "apple", "application"]
// Iterate over all entries (sorted alphabetically)
for (const [key, value] of trie) {
console.log(`${key}: ${value}`)
}
// Output: "app: 2", "apple: 1", "application: 3", "banana: 4"
// Check if key exists
console.log(Trie.has(trie, "app")) // true
// Get size
console.log(Trie.size(trie)) // 4
Trie<function (type parameter) V in <V>(self: Trie<V>): Option<[string, V]>V>) => import OptionOption<[string, function (type parameter) V in <V>(self: Trie<V>): Option<[string, V]>V]>
<function (type parameter) V in <V>(self: Trie<V>, key: string): Option<[string, V]>V>(self: Trie<V>(parameter) self: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Trie<in out Value>An immutable string-keyed map optimized for prefix lookup. Iteration yields
[key, value] pairs in key order, and update operations such as insert and
remove return new Trie values.
Example (Using a trie for prefix search)
import { Trie } from "effect"
// Create a trie with string-to-number mappings
const trie: Trie.Trie<number> = Trie.make(
["apple", 1],
["app", 2],
["application", 3],
["banana", 4]
)
// Get values by exact key
console.log(Trie.get(trie, "apple")) // Some(1)
console.log(Trie.get(trie, "grape")) // None
// Find all keys with a prefix
console.log(Array.from(Trie.keysWithPrefix(trie, "app")))
// ["app", "apple", "application"]
// Iterate over all entries (sorted alphabetically)
for (const [key, value] of trie) {
console.log(`${key}: ${value}`)
}
// Output: "app: 2", "apple: 1", "application: 3", "banana: 4"
// Check if key exists
console.log(Trie.has(trie, "app")) // true
// Get size
console.log(Trie.size(trie)) // 4
Trie<function (type parameter) V in <V>(self: Trie<V>, key: string): Option<[string, V]>V>, key: stringkey: string): import OptionOption<[string, function (type parameter) V in <V>(self: Trie<V>, key: string): Option<[string, V]>V]>
} = import TRTR.const longestPrefixOf: anylongestPrefixOf