Class Collection<T>

Maintains a collection of items, and keeps the registered indexes up to date.

Example

import { Collection } from "composable-indexes";
type Person = { name: string, age: number };
const collection = new Collection<Readonly<Person>>();

Type Parameters

  • T

    The type of the items in the collection. It is recommended to use a read-only type here.

Hierarchy

  • Collection

Constructors

constructor

Properties

indexes last store

Methods

newId propagateUpdate registerIndex

Mutations

add adjust alter delete set

Queries

forEach get toList

Constructors

constructor

Properties

Private indexes

indexes: Index<T, T>[] = []

Private last

last: Id = ...

Private store

store: IdMap<T> = ...

Methods

Private newId

Private propagateUpdate

registerIndex

  • Registers an UnregisteredIndex to a collection, returning the Index that can be used to query the collection.

    You likely want to use this before you populate the collection, as it needs to iterate over all the existing items in the collection to build the index.

    Complexity: O(n) where n is the number of items already in the collection.

    Type Parameters

    • Ix extends Index<T, T, Ix>

    Parameters

    Returns Ix

Mutations

add

  • Complexity: O(1)

    Parameters

    • value: T

      Value to add the collection

    Returns Id

    An Id that can be used to refer to the added value.

adjust

  • Updates a value in the collection, if it exists.

    Complexity: O(1)

    Parameters

    • id: Id
    • f: ((pre) => T)
        • (pre): T

        • Parameters

          • pre: T

          Returns T

    Returns void

alter

  • Most generic way to update an item in the collection.

    Complexity: O(1)

    Type Parameters

    • Ret

    Parameters

    • id: Id
    • f: ((pre) => [undefined | T, Ret])

      Takes either the existing value, or undefined if it doesn't exist, and returns a tuple of the new value and the return value. If the new value is undefined, existing item is deleted.

        • (pre): [undefined | T, Ret]

        • Parameters

          • pre: undefined | T

          Returns [undefined | T, Ret]

    Returns Ret

    Throws

    ConflictException if the index invariant is violated

    Throws

    ConditionFailedException if the precondition fails

delete

  • Complexity: O(1)

    Parameters

    Returns undefined | T

    The deleted value, or undefined if doesn't exist.

set

  • Creates or updates a item in the collection.

    Complexity: O(1)

    Parameters

    • id: Id
    • newValue: T

    Returns void

Queries

forEach

  • Parameters

    • f: ((value, id) => void)
        • (value, id): void

        • Parameters

          • value: T
          • id: Id

          Returns void

    Returns void

get

toList

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