Class: Collection

Collection()

Abstract base class for iterable collections.
The Collection class defines a unified, database-inspired interface
for both sorted and unsorted data structures. It combines abstract
collection primitives with concrete CRUD-style operations and utility
methods.

Abstract Methods:
Subclasses must implement the following:

  • n — number of items in the collection
  • has — check item membership
  • add — add a new item
  • remove — remove an existing item
  • clear — clear all items
  • get — retrieve items matching a query
  • [Symbol.iterator] — iterate over the collection

Concrete Methods:
Built on top of the abstract primitives, the base class provides:

  • CRUD operations: create, read, update, delete
  • Query helpers: query, readAll
  • Utility methods: isEmpty, let, letAll, removeAll, deleteAll

Constructor

new Collection()

Source:

Classes

Collection

Members

size

Size getter (ergonomic alias for n()). Read-only property.

Source:

Methods

(abstract) add(item) → {boolean}

Adds the given item to the collection. Semantics (allowing or rejecting duplicates) depend on the concrete subclass.

Parameters:
Name Type Description
item any

The item to add.
Source:
Returns:

True if the collection was modified.

Type
boolean

addAll(items) → {Array.<any>}

Adds all items from an iterable.

Parameters:
Name Type Description
items Iterable.<any>

Items to add.
Source:
Returns:

List of actually removed items.

Type
Array.<any>

(abstract) clear() → {boolean}

Removes all items from the collection.

Source:
Returns:

True if the collection was cleared.

Type
boolean

create(item) → {boolean}

Create (C in CRUD): Adds a new item if it is not already present.

Parameters:
Name Type Description
item any

The item to create.
Source:
Returns:

True if the collection was modified.

Type
boolean

delete(item) → {boolean}

Delete (D in CRUD): Removes an item from the collection.

Parameters:
Name Type Description
item any

The item to delete.
Source:
Returns:

True if the collection was modified.

Type
boolean

deleteAll(items) → {boolean}

Delete Many (extended CRUD): Removes all the given items from the collection. Alias of removeAll.

Parameters:
Name Type Description
items Iterable.<any>

Items to delete.
Source:
Returns:

True if all the items were removed.

Type
boolean

(abstract) get(query) → {Iterable.<any>}

Retrieves items matching a given query. In the simplest case, the query is an item, and all equivalent items are returned. Subclasses may support richer query semantics.

Parameters:
Name Type Description
query any

The query object or value.
Source:
Returns:

An iterable of all matching items.

Type
Iterable.<any>

(abstract) has(item) → {boolean}

Checks whether the collection contains the given item.

Parameters:
Name Type Description
item any

The item to test for membership.
Source:
Returns:

True if the item is present, false otherwise.

Type
boolean

isEmpty() → {boolean}

Checks whether the collection is empty.

Source:
Returns:

True if the collection has no items.

Type
boolean

let(item) → {Collection}

Adds the given item and returns the collection (fluent API).

Parameters:
Name Type Description
item any

The item to add.
Source:
Returns:

The collection itself.

Type
Collection

(abstract) n() → {number}

Returns the number of items in the collection.

Source:
Returns:
Type
number

query(query) → {Iterable.<any>}

Alias for get, for database-style terminology.

Parameters:
Name Type Description
query any

The query to evaluate.
Source:
Returns:

All matching items.

Type
Iterable.<any>

read(item) → {any|undefined}

Read (R in CRUD): Returns a single matching item, or undefined if none exist. By default, this retrieves the "first" match from get.

Parameters:
Name Type Description
item any

The item or query to read.
Source:
Returns:

The matching item, or undefined.

Type
any | undefined

readAll(query) → {Iterable.<any>}

Read All (extended CRUD): Returns all items that match the given query.

Parameters:
Name Type Description
query any

The query to evaluate.
Source:
Returns:

All matching items.

Type
Iterable.<any>

(abstract) remove(item) → {boolean}

Removes the given item from the collection.

Parameters:
Name Type Description
item any

The item to remove.
Source:
Returns:

True if the collection was modified.

Type
boolean

removeAll(items) → {Array.<any>}

Removes all given items from the collection.

Parameters:
Name Type Description
items Iterable.<any>

Items to remove.
Source:
Returns:

List of actually removed items.

Type
Array.<any>

update(oldItem, newItem, upsertopt) → {boolean}

Update (U in CRUD): Replaces an existing item with a new one. If the old item does not exist, inserts the new item if upsert is true.

Parameters:
Name Type Attributes Default Description
oldItem any

The item to be replaced.
newItem any

The new item to insert.
upsert boolean <optional>
 false

Whether to insert if oldItem is not found.
Source:
Returns:

True if updated or inserted, false otherwise.

Type
boolean