Class Arr<T>

Type Parameters

Hierarchy

Cell<Elems<T>>
- Arr (View Summary)

Index

Accessors

cells

get cells(): Elems<T>
The element cells in order; tracked when read in an effect/derive.

Returns Elems<T>
- Defined in src/core/values/arr.ts:80

length

get length(): Num
Element count as a reactive Num (structural changes only).

Returns Num
- Defined in src/core/values/arr.ts:91

values

get values(): Read<readonly T[]>
Snapshot of element values, readonly T[]; re-derives on any value or structural change. Memoized per instance.

Returns Read<readonly T[]>
- Defined in src/core/values/arr.ts:86

Constructors

constructor

new Arr<T>(items?: Elems<T>): Arr<T>
Type Parameters
- T
Parameters
- items: Elems<T> = []
Returns Arr<T>
Overrides Cell.constructor
- Defined in src/core/values/arr.ts:45

Methods

assertContains

assertContains(e: Cell<T>): void
Make e appear in this view: insert into the base if absent, then assert each view's constraint up the chain.
Parameters
- e: Cell<T>
Returns void
- Defined in src/core/values/arr.ts:188

clear

clear(): void
Empty the collection (a view removes only its visible elements).

Returns void
- Defined in src/core/values/arr.ts:198

derive

derive(this: Cell<Elems<T>>, fn: (v: Elems) => Elems): this
Read-only same-type view: the RO dual of the endo .lens. For a cross-type view use the typed static Target.derive(src, fn).
Parameters
- this: Cell<Elems<T>>
- fn: (v: Elems) => Elems
Returns this
Inherited from Cell.derive
- Defined in src/core/cell.ts:885

filter

filter(pred: CellPred<T>): Arr<T>
Subset whose elements pass pred (which reads element values, so the view re-derives reactively). Shares the element cells. insert adds to the parent and asserts the predicate.
Parameters
- pred: CellPred<T>
Returns Arr<T>
- Defined in src/core/values/arr.ts:211

groupBy

groupBy<K>(
field: (e: Cell<T>) => Writable<Cell<K>>,
opts?: { order?: readonly K[] },
): GroupArr<K, T>
Partition by a per-element key field into derived sub-Arrs, one writable filter view per bucket. move(e, key, index) writes the key field and splices the base so e lands at index in its new group. order seeds empty buckets and pins their order.
Type Parameters
- K
Parameters
- field: (e: Cell<T>) => Writable<Cell<K>>
- opts: { order?: readonly K[] } = {}
Returns GroupArr<K, T>
- Defined in src/core/values/arr.ts:285

indexOf

indexOf(e: Cell<T>): Writable<Num>
This element's index as a writable Num: reading gives its position, writing reorders (splices the reference to the rounded, clamped target). Writable on a base Arr; read-only over a derived view.
Parameters
- e: Cell<T>
Returns Writable<Num>
- Defined in src/core/values/arr.ts:98

insert

insert(v: T | Cell<T>, at?: number): Cell<T>
Insert at at (default: end). On a view, delegates through the view's insert (a filter asserts its predicate; map has none, so it throws).
Parameters
- v: T | Cell<T>
- Optionalat: number
Returns Cell<T>
- Defined in src/core/values/arr.ts:123

lens

lens(
 this: Cell<Elems<T>>,
 fwd: (v: Elems) => Elems,
 bwd: (target: Elems, current: Elems) => Elems,
): this
Endomorphic lens. A 2-arg bwd(view, current) consults the current source; a 1-arg bwd(view) reconstructs it from the view alone.
Parameters
- this: Cell<Elems<T>>
- fwd: (v: Elems) => Elems
- bwd: (target: Elems, current: Elems) => Elems
Returns this
Inherited from Cell.lens
- Defined in src/core/cell.ts:879

map

map(f: (v: T) => U, g?: (u: U, v: T) => T): Arr
Per-element map. f projects each element value; with the inverse g the mapped elements are writable lenses (editing one writes the source cell), else they're read-only. Element identity is stable: one lens per source cell, memoized.
Type Parameters
- U
Parameters
- f: (v: T) => U
- Optionalg: (u: U, v: T) => T
Returns Arr
- Defined in src/core/values/arr.ts:249

merge

merge(this: Cell<Elems<T>>, fold?: MergeFold<Elems<T>>): Cell<Elems<T>>
Backward fan-in: forwards its parent's value unchanged; on write, folds N contributors into one value. fold defaults to last-writer-wins.
Parameters
- this: Cell<Elems<T>>
- Optionalfold: MergeFold<Elems<T>>
Returns Cell<Elems<T>>
Inherited from Cell.merge
- Defined in src/core/cell.ts:914

move

move(e: Cell<T>, to: number): void
Move e to index to (rounded, clamped) in this (view's) order.
Parameters
- e: Cell<T>
- to: number
Returns void
- Defined in src/core/values/arr.ts:159

moveBefore

moveBefore(e: Cell<T>, anchor: Cell<T> | null): void
Splice e to just before anchor (or to the end when anchor is null). On a base Arr this rewrites the reference order; on a view it delegates through the view's moveBefore, where the shared anchor cell stays meaningful in the base order. No-op if e isn't present.
Parameters
- e: Cell<T>
- anchor: Cell<T> | null
Returns void
- Defined in src/core/values/arr.ts:170

peek

peek(): Elems
Returns Elems
Inherited from Cell.peek
- Defined in src/core/cell.ts:864

push

push(v: T | Cell<T>): Cell<T>
Append v (a value is wrapped in a fresh cell; a cell passes through). Returns the element cell.
Parameters
- v: T | Cell<T>
Returns Cell<T>
- Defined in src/core/values/arr.ts:117

remove

remove(e: Cell<T>): void
Remove element e (by reference). On a view, delegates through the view's remove.
Parameters
- e: Cell<T>
Returns void
- Defined in src/core/values/arr.ts:140

removeAt

removeAt(i: number): void
Remove the element at index i in this (view's) order.
Parameters
- i: number
Returns void
- Defined in src/core/values/arr.ts:153

sortBy

sortBy(key: (c: Cell<T>) => number): Arr<T>
Projection ordered by key (read off each element, so it re-sorts reactively). Shares the element cells; structural edits delegate to the base (a move/insert repositions in the base order, not the view's).
Parameters
- key: (c: Cell<T>) => number
Returns Arr<T>
- Defined in src/core/values/arr.ts:233

through

through(this: Cell<Elems<T>>, o: Optic<Elems<T>, B>): Writable<Cell>
Apply optic value(s) as a writable lens: c.through(o) ≡ lens(c, o.get, o.put); multiple optics compose left-to-right (c.through(a, b) = a then b). Cross-type, unlike the endomorphic instance .lens.
Type Parameters
- B
Parameters
- this: Cell<Elems<T>>
- o: Optic<Elems<T>, B>
Returns Writable<Cell>
Inherited from Cell.through
- Defined in src/core/cell.ts:892
through<B, C>(
 this: Cell<Elems<T>>,
 o1: Optic<Elems<T>, B>,
 o2: Optic<B, C>,
): Writable<Cell<C>>
Apply optic value(s) as a writable lens: c.through(o) ≡ lens(c, o.get, o.put); multiple optics compose left-to-right (c.through(a, b) = a then b). Cross-type, unlike the endomorphic instance .lens.
Type Parameters
- B
- C
Parameters
- this: Cell<Elems<T>>
- o1: Optic<Elems<T>, B>
- o2: Optic<B, C>
Returns Writable<Cell<C>>
Inherited from Cell.through
- Defined in src/core/cell.ts:893
through<B, C, D>(
 this: Cell<Elems<T>>,
 o1: Optic<Elems<T>, B>,
 o2: Optic<B, C>,
 o3: Optic<C, D>,
): Writable<Cell<D>>
Apply optic value(s) as a writable lens: c.through(o) ≡ lens(c, o.get, o.put); multiple optics compose left-to-right (c.through(a, b) = a then b). Cross-type, unlike the endomorphic instance .lens.
Type Parameters
- B
- C
- D
Parameters
- this: Cell<Elems<T>>
- o1: Optic<Elems<T>, B>
- o2: Optic<B, C>
- o3: Optic<C, D>
Returns Writable<Cell<D>>
Inherited from Cell.through
- Defined in src/core/cell.ts:894

`Static`coerce

coerce<C extends AnyCellCtor>(
this: C,
v: Val<Inner<InstanceType<C>>>,
): InstanceType<C>
Coerce Val<Inner<Cls>> → Cls: instance → identity, RO cell → tracked derive, literal → fresh seed.
Type Parameters
- C extends AnyCellCtor
Parameters
- this: C
- v: Val<Inner<InstanceType<C>>>
Returns InstanceType<C>
Inherited from Cell.coerce
- Defined in src/core/cell.ts:987

`Static`derive

derive<C extends AnyCellCtor, P>(
 this: C,
 parent: Read,
 fn: (v: P) => Inner<InstanceType<C>>,
): InstanceType<C>
Read-only typed view. Cls.derive(parent, fn) (1-input), Cls.derive(parents, fn) (N-input), or Cls.derive(fn) (closure). Polymorphic-this: Vec.derive(...) → Vec.
Type Parameters
- C extends AnyCellCtor
- P
Parameters
- this: C
- parent: Read
- fn: (v: P) => Inner<InstanceType<C>>
Returns InstanceType<C>
Inherited from Cell.derive
- Defined in src/core/cell.ts:932
derive<C extends AnyCellCtor, P extends readonly Read<unknown>[]>(
 this: C,
 parents: P,
 fn: (vals: ReadValues) => Inner<InstanceType<C>>,
): InstanceType<C>
Read-only typed view. Cls.derive(parent, fn) (1-input), Cls.derive(parents, fn) (N-input), or Cls.derive(fn) (closure). Polymorphic-this: Vec.derive(...) → Vec.
Type Parameters
- C extends AnyCellCtor
- P extends readonly Read<unknown>[]
Parameters
- this: C
- parents: P
- fn: (vals: ReadValues) => Inner<InstanceType<C>>
Returns InstanceType<C>
Inherited from Cell.derive
- Defined in src/core/cell.ts:937
derive<C extends AnyCellCtor>(
this: C,
fn: () => Inner<InstanceType<C>>,
): InstanceType<C>
Read-only typed view. Cls.derive(parent, fn) (1-input), Cls.derive(parents, fn) (N-input), or Cls.derive(fn) (closure). Polymorphic-this: Vec.derive(...) → Vec.
Type Parameters
- C extends AnyCellCtor
Parameters
- this: C
- fn: () => Inner<InstanceType<C>>
Returns InstanceType<C>
Inherited from Cell.derive
- Defined in src/core/cell.ts:942

`Static`fromSource

fromSource<S, R>(
 source: Read<S>,
 getter: (s: S) => Elems<R>,
 ops: {
 insert?: (v: R | Cell<R>, at?: number) => Cell<R>;
 moveBefore?: (e: Cell<R>, anchor: Cell<R> | null) => void;
 remove?: (e: Cell<R>) => void;
 },
): Arr<R>
An Arr whose elements are derived from an external source and whose structural edits rewrite that source via ops.
Type Parameters
- S
- R
Parameters
- source: Read<S>
- getter: (s: S) => Elems<R>
- ops: {
 insert?: (v: R | Cell<R>, at?: number) => Cell<R>;
 moveBefore?: (e: Cell<R>, anchor: Cell<R> | null) => void;
 remove?: (e: Cell<R>) => void;
 }
Returns Arr<R>
- Defined in src/core/values/arr.ts:59

`Static`is

is<C extends AnyCellCtor>(this: C, v: unknown): v is InstanceType<C>
Type predicate against this class: Vec.is(x) narrows x to Vec. Inherited static; works for any subclass via polymorphic this.
Type Parameters
- C extends AnyCellCtor
Parameters
- this: C
- v: unknown
Returns v is InstanceType<C>
Inherited from Cell.is
- Defined in src/core/cell.ts:981

`Static`lens

lens<C extends AnyCellCtor, P>(
 this: C,
 parent: Read,
 fwd: (v: P) => Inner<InstanceType<C>>,
 bwd: (target: Inner<InstanceType<C>>, v: P) => P,
): Writable<InstanceType<C>>
Writable lens. Cls.lens(parent, fwd, bwd) for one input, Cls.lens(parents, fwd, bwd) for N; a 2-arg bwd reads the source, a 1-arg bwd reconstructs it. Cls.lens(parent(s), spec) builds a complement-carrying lens from { init, step, fwd, bwd }.
Type Parameters
- C extends AnyCellCtor
- P
Parameters
- this: C
- parent: Read
- fwd: (v: P) => Inner<InstanceType<C>>
- bwd: (target: Inner<InstanceType<C>>, v: P) => P
Returns Writable<InstanceType<C>>
Inherited from Cell.lens
- Defined in src/core/cell.ts:952
lens<C extends AnyCellCtor, P extends readonly Read<unknown>[]>(
 this: C,
 parents: P,
 fwd: (vals: ReadValues) => Inner<InstanceType<C>>,
 bwd: (
 target: Inner<InstanceType<C>>,
 vals: ReadValues,
 ) => BackUpdates<ReadValuesOrSkip>,
): Writable<InstanceType<C>>
Writable lens. Cls.lens(parent, fwd, bwd) for one input, Cls.lens(parents, fwd, bwd) for N; a 2-arg bwd reads the source, a 1-arg bwd reconstructs it. Cls.lens(parent(s), spec) builds a complement-carrying lens from { init, step, fwd, bwd }.
Type Parameters
- C extends AnyCellCtor
- P extends readonly Read<unknown>[]
Parameters
- this: C
- parents: P
- fwd: (vals: ReadValues) => Inner<InstanceType<C>>
- bwd: (
 target: Inner<InstanceType<C>>,
 vals: ReadValues,
 ) => BackUpdates<ReadValuesOrSkip>
Returns Writable<InstanceType<C>>
Inherited from Cell.lens
- Defined in src/core/cell.ts:958
lens<C extends AnyCellCtor, P, Cm>(
 this: C,
 parent: Read,
 spec: StatefulLensSpec1<P, Inner<InstanceType<C>>, Cm>,
): Writable<InstanceType<C>>
Writable lens. Cls.lens(parent, fwd, bwd) for one input, Cls.lens(parents, fwd, bwd) for N; a 2-arg bwd reads the source, a 1-arg bwd reconstructs it. Cls.lens(parent(s), spec) builds a complement-carrying lens from { init, step, fwd, bwd }.
Type Parameters
- C extends AnyCellCtor
- P
- Cm
Parameters
- this: C
- parent: Read
- spec: StatefulLensSpec1<P, Inner<InstanceType<C>>, Cm>
Returns Writable<InstanceType<C>>
Inherited from Cell.lens
- Defined in src/core/cell.ts:964
lens<C extends AnyCellCtor, P extends readonly Read<unknown>[], Cm>(
 this: C,
 parents: P,
 spec: StatefulLensSpec<ReadValues, Inner<InstanceType<C>>, Cm>,
): Writable<InstanceType<C>>
Writable lens. Cls.lens(parent, fwd, bwd) for one input, Cls.lens(parents, fwd, bwd) for N; a 2-arg bwd reads the source, a 1-arg bwd reconstructs it. Cls.lens(parent(s), spec) builds a complement-carrying lens from { init, step, fwd, bwd }.
Type Parameters
- C extends AnyCellCtor
- P extends readonly Read<unknown>[]
- Cm
Parameters
- this: C
- parents: P
- spec: StatefulLensSpec<ReadValues, Inner<InstanceType<C>>, Cm>
Returns Writable<InstanceType<C>>
Inherited from Cell.lens
- Defined in src/core/cell.ts:969

`Static`pin

pin<C extends AnyCellCtor>(
this: C,
v: Inner<InstanceType<C>>,
): Writable<InstanceType<C>>
Writable-shaped constant: always reads v, absorbs writes (parentless sink lens), for APIs demanding bidirectionality.
Type Parameters
- C extends AnyCellCtor
Parameters
- this: C
- v: Inner<InstanceType<C>>
Returns Writable<InstanceType<C>>
Inherited from Cell.pin
- Defined in src/core/cell.ts:1000

Properties

`Readonly`_t

_t: { equals: <E>(a: readonly E[], b: readonly E[]) => boolean }

Type Declaration

equals: <E>(a: readonly E[], b: readonly E[]) => boolean

name

name: string | undefined

Optional debug label (cell(0, { name })); used by errors and graph dumps.

`Readonly`value

value: Elems

`Static`traits

traits: { equals: <E>(a: readonly E[], b: readonly E[]) => boolean } = ...

Type Declaration

equals: <E>(a: readonly E[], b: readonly E[]) => boolean

Class Arr<T>

Type Parameters

Hierarchy

Index

Accessors

Constructors

Methods

Properties

Accessors

cells

Returns Elems<T>

length

Returns Num

values

Returns Read<readonly T[]>

Constructors

constructor

Type Parameters

Parameters

Returns Arr<T>

Methods

assertContains

Parameters

Returns void

clear

Returns void

derive

Parameters

Returns this

filter

Parameters

Returns Arr<T>

groupBy

Type Parameters

Parameters

Returns GroupArr<K, T>

indexOf

Parameters

Returns Writable<Num>

insert

Parameters

Returns Cell<T>

lens

Parameters

Returns this

map

Type Parameters

Parameters

Returns Arr<U>

merge

Parameters

Returns Cell<Elems<T>>

move

Parameters

Returns void

moveBefore

Parameters

Returns void

peek

Returns Elems

push

Parameters

Returns Cell<T>

remove

Parameters

Returns void

removeAt

Parameters

Returns void

sortBy

Parameters

Returns Arr<T>

through

Type Parameters

Parameters

Returns Writable<Cell<B>>

Type Parameters

Parameters

Returns Writable<Cell<C>>

Type Parameters

`Static`coerce

`Static`derive

`Static`fromSource

`Static`is

`Static`lens

`Static`pin

`Readonly`_t

`Readonly`value

`Static`traits