Class HashDict<K, V>

A simple hash-based dictionary that only allows one item with same key.

import { HashDict } from "scl"

Most methods in this collection, given that a proper hashing function is set up, are in Θ(1 + n/k). If you're out of luck, this characteristic can grow to O(n).

When a new entry is added with a key that is already taken, the dictionary will replace the corresponding entry with the new one.

const d = new HashDict<number, string>()
d.emplace(1, 'foo')
assert.strictEqual(d.getValue(1), 'foo')
d.emplace(1, 'bar')
assert.strictEqual(d.getValue(1), 'bar')

Type Parameters

  • K

    The type of key of a given entry.

  • V

    The type of value associated with the given key.

Hierarchy

  • DictBase<K, V>
    • HashDict

Constructors

constructor

Accessors

size

Methods

[iterator] add clear clone delete deleteAll deleteAt deleteKey emplace equalKeys findKey getValue has hasKey toRange

Constructors

constructor

  • new HashDict<K, V>(
        opts?:
            | Iterable<[K, V], any, any>
            | HashIndex<[K, V], K>
            | HashDictOptions<K, V>,
    ): HashDict<K, V>

  • Construct a new hash-based dictionary.

    const d = new HashDict<number, string>()

    Similar to JavaScript's built-in map type, the constructor accepts a list of key-value pairs that will immediately be added to the resulting dictionary.

    const d = new HashDict<number, string>([
      [1, 'one'],
      [2, 'two']
    ])

    The dictionary can be tweaked by providing a HashDictOptions object, which allows to configure things like the default hashing function and value equality.

    const d = new HashDict<number, string>({
      hash: num => num,
      keysEqual: (a, b) => a === b,
      valuesEqual: (a, b) => a === b,
      elements: [[1, 'one'], [2, 'two']]
    })

    Type Parameters

    • K
    • V

    Parameters

    • opts: Iterable<[K, V], any, any> | HashIndex<[K, V], K> | HashDictOptions<K, V> = {}

    Returns HashDict<K, V>

Accessors

size

  • get size(): number

  • Count the amount of elements in the collection.

    ⚠️ In most cases, this should be an O(1) operation. However, there are cases where this can be an O(n) operation. Therefore, it is recommended to always cache the result in a local variable.

    Returns number

Methods

[iterator]

  • "[iterator]"(): IterableIterator<[K, V], any, any>

  • Returns IterableIterator<[K, V], any, any>

add

  • add(element: [K, V], hint?: any): AddResult<[K, V]>

  • Add an element to the collection. If the element already exists, update its value.

    The location where the element is placed depends on the collection type, and in the generic case there is no guarantee on the location where it is inserted.

    This method returns a pair with the first element indicating whether the element was added, while the second element refers to the actual location of the element.

    Parameters

    • element: [K, V]
    • Optionalhint: any

      A transparent object obtained by getAddHint.

    Returns AddResult<[K, V]>

clear

  • clear(): void

  • Remove all elements from this collection, effectively setting the collection to the empty collection.

    Returns void

clone

delete

  • delete(element: [K, V]): boolean

  • Remove an element from the collection. If multiple elements are matched, the collection picks one of them.

    Parameters

    • element: [K, V]

    Returns boolean

    true if the element was found, false otherwise.

deleteAll

  • deleteAll(element: [K, V]): number

  • Remove an element from the collection. If multiple elements are matched, the collection removes all of them.

    Parameters

    • element: [K, V]

    Returns number

    The amount of elements that was removed.

deleteAt

  • deleteAt(position: Cursor<[K, V]>): void

  • Remove the element pointed to by the iterator result from this collection.

    Parameters

    Returns void

deleteKey

  • deleteKey(key: K): number

  • Delete a pair from the underlying collection that has the given key as key.

    Returns the amount of items that have been deleted.

    Parameters

    • key: K

    Returns number

emplace

  • emplace(key: K, value: V): [boolean, Cursor<[K, V]>]

  • Creates a new pair and inserts it in the underlying collection.

    Parameters

    • key: K
    • value: V

    Returns [boolean, Cursor<[K, V]>]

equalKeys

findKey

  • findKey(key: K): undefined | Cursor<[K, V]>

  • Similar to Dict.getValue, except that it returns the pair that was inserted in the collection.

    Parameters

    • key: K

    Returns undefined | Cursor<[K, V]>

getValue

  • getValue(key: K): undefined | V

  • Get the value that is associated with the given key.

    Parameters

    • key: K

    Returns undefined | V

has

  • has(element: [K, V]): boolean

  • Checks if the collection holds the given element.

    Parameters

    • element: [K, V]

      The element to check membership of.

    Returns boolean

    True if the collections holds the given element, false otherwise.

hasKey

  • hasKey(key: K): boolean

  • Checks whether there a pair in this collection that has the given key.

    Parameters

    • key: K

    Returns boolean

toRange

  • toRange(): Range<[K, V]>

  • Converts the entire collection to a range.

    Returns Range<[K, V]>

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