Extended native JavaScript Array which provides indexed lookup similar to native Map.

• Installation
• Description
• Synopsis
• Details
• API
• indexable-array
  • Table of contents
    • Classes
• Classes
• Class: default<I, DK, OK, TH>
  • Type parameters
  • Hierarchy
  • Table of contents
    • Properties
    • Accessors
    • Methods
  • Properties
    • indexedKeys
  • Accessors
    • defaultKey
  • Methods
    • concat
    • disableIndex
    • enableIndex
    • filter
    • flatMap
    • get
    • getAll
    • getAllIndexes
    • getIndex
    • getMaybe
    • getSure
    • has
    • map
    • mapToArray
    • push
    • set
    • slice
    • sort
    • sortBy
    • splice
    • withDefaultIndex
    • from
    • throwingFrom

npm install indexable-array

indexable-array extends native JavaScript array and provides indexed lookup features similar to native Map by using Proxy for shallow change detection.

import IndexableArray, { Self } from "indexable-array";

const users = new IndexableArray({ id: 23, name: "George" }, { id: 92, name: "George" }).addIndex("name", Self);
const otherUsers = new IndexableArray({ id: 12, name: "Hans" }, { id: 18, name: "Tanja" }).addIndex("name").addSelfIndex();

Array.isArray(users); // true
users.getIndex("George"); // 1
users.get("George"); // Get first George: { id: 23, name: "George"}
users.get("George", { fromIndex: 1 }); // Get first George starting from index 1: { id: 23, name: "George"}
users.getAllIndexes("George"); // [0, 1]

// Replace George with Henry
const newUser = { id: 21, name: "Henry" };
users[0] = newUser;
users.getIndex(newUser); // 0 - It is possible to index whole object by { selfIndex: true } option.

// Add another Henry
users.splice(1, 1, { id: 34, name: "Henry" });
users.getAllIndexes("Henry"); // [0, 1];

// You may want to disable en re-enable index for heavy updates for performance reasons.
users.disableIndex(); // Disable index before heavy updates.
// ... many many many updates here
users.enableIndex(); // Index is recreated from scratch.

// Do NOT change deeply nested values in indexed fields.
// users[0].name = "DON'T DO THIS";       // WRONG: Sub fields (i.e. [0]."name") of the array is not watched, so index does not get updated.

// To change nested values use `set()`
users.set(0, "name", "OK"); // Index updated.

// or (not preferred because of expensive index creation for a small update)
users.disableIndex();
users[0].name = "Prefer set()";
users.enableIndex(); // Index is recreated from scratch.

• Written in TypeScript.
• Is a native Array (Array.isArray(indexableArray) === true), so supports all array features.
• 100% test coverage.
• Tracks all shallow changes via by using Proxy
• Limited support for updating deep properties via set() method.
• Uses map to index for very fast lookups.
• Uses binary search for updates for faster index update.
• Disables and recreates index from scratch automatically for heavy update operations like splice if above threshold..
• Indexing may be disabled and re-enabled for heavy update operations manually.
• Uses binary search for indexOf(), lastIndexOf(), has() if user added self index.
• Methods such as map(), filter(), slice() returns IndexedArray. Additionally provides mapIndexed() method.

indexable-array

• default

indexable-array / default

Extended native array class to access array elements by fast key lookups using binary search. Used for storing objects.

import IndexableArray, { Self } from "indexable-array";
const users = new IndexableArray({ id: 23, name: "Geroge" }, { id: 96, name: "Lisa" }).addIndex("name");
Array.isArray(users); // true
users.get("George"); // { id: 23, name: "George"}
const user = { id: 21, name: "Henry" };
users[0] = user;
users.getIndex(user); // 0 - It is possible to index whole object by { selfIndex: true } option.
users.splice(1, 1, { id: 34, name: "Henry" });
users.getAllIndexes("Henry"); // [0, 1];

users[0].name = "DON'T DO THIS"; // WRONG: Sub fields (i.e. [0]."name") of the array is not watched, so index does not get updated.
users.set(0, "name", "OK"); // Index updated.
users.disableIndex();
users[0].name = "THIS IS OK NOW";
users.enableIndex(); // Index is recreated from scratch.

• Array<I>

  ↳ default

• indexedKeys

• defaultKey

• concat
• disableIndex
• enableIndex
• filter
• flatMap
• get
• getAll
• getAllIndexes
• getIndex
• getMaybe
• getSure
• has
• map
• mapToArray
• push
• set
• slice
• sort
• sortBy
• splice
• withDefaultIndex
• from
• throwingFrom

• Readonly indexedKeys: Set<DK | OK>

Set of the indexed key names. $$self is used for the whole value.

const users = new IndexableArray({ id: 23, name: "Geroge" }, { id: 96, name: "Lisa" }).addSelfIndex().addIndex("name");
users.indexedArray; // ["$$self", "name"]

Defined in: index.ts:77

• defaultKey(): DK

Returns: DK

Defined in: index.ts:200

▸ concat(...items: ConcatArray<I>[]): default<I, DK, OK, TH>

Returns: default<I, DK, OK, TH>

Defined in: index.ts:672

▸ concat(...items: (I | ConcatArray<I>)[]): default<I, DK, OK, TH>

| Name | Type | | ---------- | ---- | -------------------- | | ...items | (I | ConcatArray<I>)[] |

Returns: default<I, DK, OK, TH>

Defined in: index.ts:673

▸ disableIndex(): void

Disables indexing of the array. It may be used to disable temporarily

• to do heavy updates for performance reasons,
• to do operations in sub fields. If indexing is not needed anymore, it is suggested to create a new native non-extended array and copy values into it for avoiding performance penalty of proxy array used in this library.

indexedArray.disableIndex();
indexedArray[0].name = "THIS IS OK NOW";
indexedArray.enableIndex(); // Index is recreated from scratch.

see {IndexedArray#enableIndex} method.

Returns: void

Defined in: index.ts:857

▸ enableIndex(): void

Enables indexing and recreates index from scratch.

see {IndexedArray#disableIndex} method.

Returns: void

Defined in: index.ts:866

▸ filter<S>(callbackfn: (value: I, index: number, array: default<I, DK, OK, TH>) => value is S, thisArg?: any): default<S, DK, OK, TH>

Returns: default<S, DK, OK, TH>

Defined in: index.ts:466

▸ filter(callbackfn: Callback<I, DK, OK, TH, unknown>, thisArg?: any): default<I, DK, OK, TH>

Returns: default<I, DK, OK, TH>

Defined in: index.ts:471

▸ flatMap<U, DK2, OK2, This>(callbackFn: CallbackThis<I, DK, OK, TH, U | readonly U[], This>, defaultKey?: DK2, ...indexKeys: OK2[]): default<U, DK2, Exclude<OK2, DK2>, TH>

| Name | Type | Default | | ------ | ------------ | ------------------------------ | ----------- | --- | | U | Pick<I, DK | OK> | - | | DK2 | string | number | symbol | DK | | OK2 | string | number | symbol | OK | | This | undefined | Record<string, unknown> | undefined |

| Name | Type | | -------------- | ------------------------------- | -------------------- | | callbackFn | CallbackThis<I, DK, OK, TH, U | readonly U[], This> | | defaultKey? | DK2 | | ...indexKeys | OK2[] |

Returns: default<U, DK2, Exclude<OK2, DK2>, TH>

Defined in: index.ts:558

▸ flatMap<U, DK2, OK2, This>(callbackFn: CallbackThis<I, DK, OK, TH, U | readonly U[], This>, thisArg: This, defaultKey?: DK2, ...indexKeys: OK2[]): default<U, DK2, Exclude<OK2, DK2>, TH>

| Name | Type | Default | | ------ | ------------ | ------------------------------ | ----------- | --- | | U | Pick<I, DK | OK> | - | | DK2 | string | number | symbol | DK | | OK2 | string | number | symbol | OK | | This | undefined | Record<string, unknown> | undefined |

| Name | Type | | -------------- | ------------------------------- | -------------------- | | callbackFn | CallbackThis<I, DK, OK, TH, U | readonly U[], This> | | thisArg | This | | defaultKey? | DK2 | | ...indexKeys | OK2[] |

Returns: default<U, DK2, Exclude<OK2, DK2>, TH>

Defined in: index.ts:569

▸ flatMap<U, DK2, OK2, This>(callbackFn: CallbackThis<I, DK, OK, TH, U | readonly U[], This>, defaultKey: DK2, ...indexKeys: OK2[]): default<U, DK2, Exclude<OK2, DK2>, TH>

| Name | Type | Default | | ------ | ------------------------------ | ------------------------------ | ----------- | ------- | | U | Record<string, unknown> | - | | DK2 | string | number | symbol | - | | OK2 | string | number | symbol | never | | This | undefined | Record<string, unknown> | undefined |

| Name | Type | | -------------- | ------------------------------- | -------------------- | | callbackFn | CallbackThis<I, DK, OK, TH, U | readonly U[], This> | | defaultKey | DK2 | | ...indexKeys | OK2[] |

Returns: default<U, DK2, Exclude<OK2, DK2>, TH>

Defined in: index.ts:581

▸ flatMap<U, DK2, OK2, This>(callbackFn: CallbackThis<I, DK, OK, TH, U | readonly U[], This>, thisArg: This, defaultKey: DK2, ...indexKeys: OK2[]): default<U, DK2, Exclude<OK2, DK2>, TH>

| Name | Type | Default | | ------ | ------------------------------ | ------------------------------ | ----------- | ------- | | U | Record<string, unknown> | - | | DK2 | string | number | symbol | - | | OK2 | string | number | symbol | never | | This | undefined | Record<string, unknown> | undefined |

| Name | Type | | -------------- | ------------------------------- | -------------------- | | callbackFn | CallbackThis<I, DK, OK, TH, U | readonly U[], This> | | thisArg | This | | defaultKey | DK2 | | ...indexKeys | OK2[] |

Returns: default<U, DK2, Exclude<OK2, DK2>, TH>

Defined in: index.ts:592

▸ flatMap<U, This>(callbackFn: CallbackThis<I, DK, OK, TH, U | readonly U[], This>, thisArg?: This, ...rest: never[]): default<U, AvailableDefaultIndex<U, DK, OK>, Exclude<Extract<OK, keyof U>, AvailableDefaultIndex<U, DK, OK>>, TH>

| Name | Type | Default | | ------ | ------------------------------ | ------------------------------ | ----------- | | U | Record<string, unknown> | - | | This | undefined | Record<string, unknown> | undefined |

| Name | Type | | ------------ | ------------------------------- | -------------------- | | callbackFn | CallbackThis<I, DK, OK, TH, U | readonly U[], This> | | thisArg? | This | | ...rest | never[] |

Returns: default<U, AvailableDefaultIndex<U, DK, OK>, Exclude<Extract<OK, keyof U>, AvailableDefaultIndex<U, DK, OK>>, TH>

Defined in: index.ts:604

▸ flatMap<U, This>(callbackFn: CallbackThis<I, DK, OK, TH, U | readonly U[], This>, thisArg?: This, ...rest: never[]): default<U, AvailableDefaultIndex<U, DK, OK>, Exclude<Extract<OK, keyof U>, AvailableDefaultIndex<U, DK, OK>>, TH>

| Name | Type | Default | | ------ | ----------- | ------------------------------ | ----------- | | U | unknown | - | | This | undefined | Record<string, unknown> | undefined |

| Name | Type | | ------------ | ------------------------------- | -------------------- | | callbackFn | CallbackThis<I, DK, OK, TH, U | readonly U[], This> | | thisArg? | This | | ...rest | never[] |

Returns: default<U, AvailableDefaultIndex<U, DK, OK>, Exclude<Extract<OK, keyof U>, AvailableDefaultIndex<U, DK, OK>>, TH>

Defined in: index.ts:610

▸ get<K, TH2>(value: I[K], __namedParameters?: { fromIndex?: undefined | number ; key?: undefined | K ; throwUnknown?: undefined | TH2 }): TH2 extends true ? I : undefined | I

Returns the first item at which a given indexed value can be found in the array. According to construction option or throwUnknown option, returns undefined or throws exception if value cannot be found.

| Name | Type | Default | | ----- | ----------- | --------- | -------- | --- | | K | string | number | symbol | - | | TH2 | undefined | boolean | TH |

• value: I[K]

is indexed value to search for.

• __namedParameters: object

| Name | Type | | --------------- | ----------- | -------- | | fromIndex? | undefined | number | | key? | undefined | K | | throwUnknown? | undefined | TH2 |

Returns: TH2 extends true ? I : undefined | I

the first item with given indexed value in the array; undefined if not found.

Defined in: index.ts:743

▸ getAll<K>(value: I[K], __namedParameters?: { key?: undefined | K }): I[]

Returns all items at which a given indexed value can be found in the array, or empty array if it is not present.

| Name | Type | | ---- | -------- | -------- | -------- | | K | string | number | symbol |

• value: I[K]

is indexed value to search for.

• __namedParameters: object

| Name | Type | | ------ | ----------- | --- | | key? | undefined | K |

Returns: I[]

all items with given indexed value in the array; Empty array if not found.

Defined in: index.ts:799

▸ getAllIndexes<K>(value: I[K], __namedParameters?: { key?: undefined | K }): number[]

Returns all indexes at which a given indexed value can be found in the array, or empty array if it is not present.

| Name | Type | | ---- | -------- | -------- | -------- | | K | string | number | symbol |

• value: I[K]

indexed value to search for.

• __namedParameters: object

| Name | Type | | ------ | ----------- | --- | | key? | undefined | K |

Returns: number[]

all indexes of the element in the array; Empty array if not found.

Defined in: index.ts:727

▸ getIndex<K>(value: I[K], __namedParameters?: { fromIndex?: undefined | number ; key?: undefined | K }): number

Returns the first index at which a given indexed value can be found in the array, or -1 if it is not present.

| Name | Type | | ---- | -------- | -------- | -------- | | K | string | number | symbol |

• value: I[K]

indexed value to search for.

• __namedParameters: object

| Name | Type | | ------------ | ----------- | -------- | | fromIndex? | undefined | number | | key? | undefined | K |

Returns: number

the first index of the element in the array; -1 if not found.

Defined in: index.ts:704

▸ getMaybe<K>(value: I[K], __namedParameters?: { fromIndex?: undefined | number ; key?: undefined | K }): undefined | I

Returns the first item at which a given indexed value can be found in the array. Returns undefined if value cannot be found.

| Name | Type | | ---- | -------- | -------- | -------- | | K | string | number | symbol |

• value: I[K]

is indexed value to search for.

• __namedParameters: object

| Name | Type | | ------------ | ----------- | -------- | | fromIndex? | undefined | number | | key? | undefined | K |

Returns: undefined | I

is the first item with given indexed value in the array; undefined if not found.

Defined in: index.ts:784

▸ getSure<K>(value: I[K], __namedParameters?: { fromIndex?: undefined | number ; key?: undefined | K }): I

Returns the first item at which a given indexed value can be found in the array, or throws exception if it is not present.

| Name | Type | | ---- | -------- | -------- | -------- | | K | string | number | symbol |

• value: I[K]

is indexed value to search for.

• __namedParameters: object

| Name | Type | | ------------ | ----------- | -------- | | fromIndex? | undefined | number | | key? | undefined | K |

Returns: I

the first item with given indexed value in the array; undefined if not found.

Defined in: index.ts:771

▸ has<K>(value: I[K], __namedParameters?: { fromIndex?: undefined | number ; key?: undefined | K }): boolean

Determines whether an array includes a certain indexed value among its entries' keys, returning true or false as appropriate.

| Name | Type | | ---- | -------- | -------- | -------- | | K | string | number | symbol |

• value: I[K]

is indexed value to search for.

• __namedParameters: object

| Name | Type | | ------------ | ----------- | -------- | | fromIndex? | undefined | number | | key? | undefined | K |

Returns: boolean

true if indexed value is found among array's entries' keys.

Defined in: index.ts:814

▸ map<U, DK2, OK2>(callbackFn: Callback<I, DK, OK, TH, U>, defaultKey?: DK2, ...indexKeys: OK2[]): default<U, DK2, Exclude<OK2, DK2>, TH>

| Name | Type | Default | | ----- | ------------ | -------- | -------- | --- | | U | Pick<I, DK | OK> | - | | DK2 | string | number | symbol | DK | | OK2 | string | number | symbol | OK |

Returns: default<U, DK2, Exclude<OK2, DK2>, TH>

Defined in: index.ts:481

▸ map<U, DK2, OK2>(callbackFn: Callback<I, DK, OK, TH, U>, thisArg: Record<string, unknown>, defaultKey?: DK2, ...indexKeys: OK2[]): default<U, DK2, Exclude<OK2, DK2>, TH>

| Name | Type | Default | | ----- | ------------ | -------- | -------- | --- | | U | Pick<I, DK | OK> | - | | DK2 | string | number | symbol | DK | | OK2 | string | number | symbol | OK |

Returns: default<U, DK2, Exclude<OK2, DK2>, TH>

Defined in: index.ts:487

▸ map<U, DK2, OK2>(callbackFn: Callback<I, DK, OK, TH, U>, defaultKey: DK2, ...indexKeys: OK2[]): default<U, DK2, Exclude<OK2, DK2>, TH>

| Name | Type | Default | | ----- | ------------------------------ | -------- | -------- | ------- | | U | Record<string, unknown> | - | | DK2 | string | number | symbol | - | | OK2 | string | number | symbol | never |

Returns: default<U, DK2, Exclude<OK2, DK2>, TH>

Defined in: index.ts:494

▸ map<U, DK2, OK2>(callbackFn: Callback<I, DK, OK, TH, U>, thisArg: Record<string, unknown>, defaultKey: DK2, ...indexKeys: OK2[]): default<U, DK2, Exclude<OK2, DK2>, TH>

| Name | Type | Default | | ----- | ------------------------------ | -------- | -------- | ------- | | U | Record<string, unknown> | - | | DK2 | string | number | symbol | - | | OK2 | string | number | symbol | never |

Returns: default<U, DK2, Exclude<OK2, DK2>, TH>

Defined in: index.ts:500

▸ map<U>(callbackFn: Callback<I, DK, OK, TH, U>, thisArg?: Record<string, unknown>): default<U, AvailableDefaultIndex<U, DK, OK>, Exclude<Extract<OK, keyof U>, AvailableDefaultIndex<U, DK, OK>>, TH>

Returns: default<U, AvailableDefaultIndex<U, DK, OK>, Exclude<Extract<OK, keyof U>, AvailableDefaultIndex<U, DK, OK>>, TH>

Defined in: index.ts:507

▸ map<U>(callbackFn: Callback<I, DK, OK, TH, U>, thisArg?: Record<string, unknown>): default<U, AvailableDefaultIndex<U, DK, OK>, Exclude<Extract<OK, keyof U>, AvailableDefaultIndex<U, DK, OK>>, TH>

Returns: default<U, AvailableDefaultIndex<U, DK, OK>, Exclude<Extract<OK, keyof U>, AvailableDefaultIndex<U, DK, OK>>, TH>

Defined in: index.ts:512

▸ mapToArray<U>(callbackfn: Callback<I, DK, OK, TH, U | readonly U[]>, thisArg?: any): U[]

Creates a new base Array (not IndexableArray) with the results of calling a provided function on every element in the calling array.

const usersWithName = new IndexableArray({ id: 23, name: "Geroge" }, { id: 96, name: "Lisa" }).addIndex("name");
const baseArray = usersWithName.mapToArray((user) => ({ id: user.id, nick: name.substring(0, 2) })); // Normal base array.

see {@link IndexableArray#map} to get an IndexableArray.

| Name | Type | Description | | ------------ | --------------------------- | ------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------- | | callbackfn | Callback<I, DK, OK, TH, U | readonly U[]> | is function that produces an element of the new Array, taking three arguments: value, index and indexableArray. | | thisArg? | any | is value to use as this when executing callback. |

Returns: U[]

a new Array with each element being the result of the callback function.

Defined in: index.ts:664

▸ push(...items: I[]): number

Returns: number

Defined in: index.ts:422

▸ set(position: number, path: string, value: any): void

Sets value at path of the object, which is one of the entires of array. To update fields of the objects, this method should be used. Otherwise index cannot be updated, because sub fileds are not tracked for chage detection.

indexedArray[0].name = "DON'T DO THIS"; // WRONG: Sub fields (i.e. [0]."name") of the array is not watched, so index does not get updated.
indexedArray.set(0, "name", "OK"); // Index updated.

Returns: void

Defined in: index.ts:831

▸ slice(start?: number, end?: number): default<I, DK, OK, TH>

Returns: default<I, DK, OK, TH>

Defined in: index.ts:668

▸ sort(compareFn?: (a: I, b: I) => number): default<I, DK, OK, TH>

Returns: default<I, DK, OK, TH>

Defined in: index.ts:441

▸ sortBy(key?: DK | OK): default<I, DK, OK, TH>

Sorts the elements of an array by given key in place and returns the sorted array.

| Name | Type | Default value | Description | | ----- | ---- | ------------- | ----------- | ---------------------------- | | key | DK | OK | ... | is the key to sort array by. |

Returns: default<I, DK, OK, TH>

this instance.

Defined in: index.ts:454

▸ splice(start: number, deleteCount?: number, ...items: I[]): I[]

Returns: I[]

Defined in: index.ts:429

▸ withDefaultIndex<K>(key: K): default<I, K, OK, TH>

Sets default index key to be used with lookup functions. Returns same instance.

const input = [
  { id: 23, name: "Geroge" },
  { id: 96, name: "Lisa" },
];
let users = new IndexableArray(...input).addIndex("name", "id"); // "name" is default index
users = users.withDefaultIndex("id"); // "id" is default index. Assignment is used for TypeScript to assign right type to variable.

| Name | Type | | ---- | -------- | -------- | -------- | | K | string | number | symbol |

Returns: default<I, K, OK, TH>

this object.

Defined in: index.ts:690

▸ Staticfrom<I2, DK2, DK3, OK2, OK3, TH2>(indexableArray: default<I2, DK2, OK2, TH2>, defaultKey?: DK3, ...indexKeys: OK3[]): default<I2, DK3, Exclude<OK3, DK3>, TH2>

| Name | Type | Default | | ----- | --------- | -------- | -------- | ------- | | I2 | unknown | - | | DK2 | string | number | symbol | - | | DK3 | string | number | symbol | DK2 | | OK2 | string | number | symbol | never | | OK3 | string | number | symbol | OK2 | | TH2 | boolean | false |

Returns: default<I2, DK3, Exclude<OK3, DK3>, TH2>

Defined in: index.ts:95

▸ Staticfrom<I2, DK2, OK2>(arrayLike: Iterable<I2> | ArrayLike<I2>, defaultKey: DK2, ...indexKeys: OK2[]): default<I2, DK2, Exclude<OK2, DK2>, false>

| Name | Type | Default | | ----- | -------- | -------- | -------- | ------- | | I2 | - | - | | DK2 | string | number | symbol | - | | OK2 | string | number | symbol | never |

| Name | Type | | -------------- | --------------- | ---------------- | | arrayLike | Iterable<I2> | ArrayLike<I2> | | defaultKey | DK2 | | ...indexKeys | OK2[] |

Returns: default<I2, DK2, Exclude<OK2, DK2>, false>

Defined in: index.ts:108

▸ StaticthrowingFrom<I2, DK2, DK3, OK2, OK3, TH2>(indexableArray: default<I2, DK2, OK2, TH2>, defaultKey?: DK3, ...indexKeys: OK3[]): default<I2, DK3, Exclude<OK3, DK3>, true>

| Name | Type | Default | | ----- | --------- | -------- | -------- | ------- | | I2 | unknown | - | | DK2 | string | number | symbol | - | | DK3 | string | number | symbol | DK2 | | OK2 | string | number | symbol | never | | OK3 | string | number | symbol | OK2 | | TH2 | boolean | false |

Returns: default<I2, DK3, Exclude<OK3, DK3>, true>

Defined in: index.ts:154

▸ StaticthrowingFrom<I2, DK2, OK2>(arrayLike: Iterable<I2> | ArrayLike<I2>, defaultKey: DK2, ...indexKeys: OK2[]): default<I2, DK2, Exclude<OK2, DK2>, true>

| Name | Type | Default | | ----- | -------- | -------- | -------- | ------- | | I2 | - | - | | DK2 | string | number | symbol | - | | OK2 | string | number | symbol | never |

| Name | Type | | -------------- | --------------- | ---------------- | | arrayLike | Iterable<I2> | ArrayLike<I2> | | defaultKey | DK2 | | ...indexKeys | OK2[] |

Returns: default<I2, DK2, Exclude<OK2, DK2>, true>

Defined in: index.ts:167