Class Event<K, D>

An immutable event made of a temporal key and typed payload data.

Example

const event = new Event(
  new Time(new Date("2025-01-01T00:00:00.000Z")),
  { cpu: 0.42, host: "api-1" },
);

event.get("cpu"); // 0.42
event.timeRange(); // TimeRange for the event extent

Type Parameters

K extends EventKey
D

Index

Constructors

constructor

Methods

asInterval asTime asTimeRange begin collapse contains data end get intersection isAfter isBefore key merge overlaps rename select set timeRange trim type withKey

Constructors

constructor

new Event<K extends EventKey, D>(key: K, data: D): Event<K, D>
Example: new Event(new Time(Date.now()), { value: 1 }). Creates an immutable event from a key and typed payload object.
Type Parameters
- K extends EventKey
- D
Parameters
- key: K
- data: D
Returns Event<K, D>
- Defined in packages/core/src/Event.ts:47

Methods

asInterval

asInterval(value: IntervalValue): Event<Interval, D>
Example: event.asInterval("bucket-a"). Converts the event key to a labeled Interval covering the same extent.
Parameters
- value: IntervalValue
Returns Event<Interval, D>
- Defined in packages/core/src/Event.ts:250
asInterval(getValue: (event: Event<K, D>) => IntervalValue): Event<Interval, D>
Example: event.asInterval("bucket-a"). Converts the event key to a labeled Interval covering the same extent.
Parameters
- getValue: (event: Event<K, D>) => IntervalValue
Returns Event<Interval, D>
- Defined in packages/core/src/Event.ts:251

asTime

asTime(options?: { at?: "begin" | "end" | "center" }): Event<Time, D>
Example: event.asTime({ at: "center" }). Converts the event key to a point-in-time key using the supplied anchor within the current extent.
Parameters
- options: { at?: "begin" | "end" | "center" } = {}
Returns Event<Time, D>
- Defined in packages/core/src/Event.ts:231

asTimeRange

asTimeRange(): Event<TimeRange, D>
Example: event.asTimeRange(). Converts the event key to an unlabeled TimeRange covering the same extent.

Returns Event<TimeRange, D>
- Defined in packages/core/src/Event.ts:243

begin

begin(): number
Example: event.begin(). Returns the inclusive event start in milliseconds since epoch.

Returns number
- Defined in packages/core/src/Event.ts:187

collapse

collapse<
    const Keys extends readonly (keyof D)[],
    Name extends string,
    R extends ScalarValue,
>(
    keys: Keys,
    output: Name,
    reducer: (values: Pick<D, Keys[number]>) => R,
): Event<K, Readonly<Omit<D, Keys[number]> & Record<Name, R>>>
Example: event.collapse(["in", "out"], "avg", fn). Collapses selected payload fields into a single derived field using the supplied reducer.
Type Parameters
- const Keys extends readonly (keyof D)[]
- Name extends string
- R extends ScalarValue
Parameters
- keys: Keys
- output: Name
- reducer: (values: Pick<D, Keys[number]>) => R
Returns Event<K, Readonly<Omit<D, Keys[number]> & Record<Name, R>>>
- Defined in packages/core/src/Event.ts:118
collapse<
    const Keys extends readonly (keyof D)[],
    Name extends string,
    R extends ScalarValue,
>(
    keys: Keys,
    output: Name,
    reducer: (values: Pick<D, Keys[number]>) => R,
    options: { append: true },
): Event<K, Readonly<D & Record<Name, R>>>
Example: event.collapse(["in", "out"], "avg", fn). Collapses selected payload fields into a single derived field using the supplied reducer.
Type Parameters
- const Keys extends readonly (keyof D)[]
- Name extends string
- R extends ScalarValue
Parameters
- keys: Keys
- output: Name
- reducer: (values: Pick<D, Keys[number]>) => R
- options: { append: true }
Returns Event<K, Readonly<D & Record<Name, R>>>
- Defined in packages/core/src/Event.ts:128

contains

contains(other: TemporalLike): boolean
Example: event.contains(time). Returns true when the event extent fully contains the supplied temporal value.
Parameters
- other: TemporalLike
Returns boolean
- Defined in packages/core/src/Event.ts:202

data

data(): Readonly<D>
Example: event.data(). Returns the immutable event payload.

Returns Readonly<D>
- Defined in packages/core/src/Event.ts:69

end

end(): number
Example: event.end(). Returns the inclusive event end in milliseconds since epoch.

Returns number
- Defined in packages/core/src/Event.ts:192

get

get<Field extends string | number | symbol>(field: Field): Readonly<D>[Field]
Example: event.get("value"). Returns a single payload field by name.
Type Parameters
- Field extends string | number | symbol
Parameters
- field: Field
Returns Readonly<D>[Field]
- Defined in packages/core/src/Event.ts:74

intersection

intersection(other: TemporalLike): TimeRange | undefined
Example: event.intersection(range). Returns the temporal intersection of the event extent and the supplied value, if any.
Parameters
- other: TemporalLike
Returns TimeRange | undefined
- Defined in packages/core/src/Event.ts:217

isAfter

isAfter(other: TemporalLike): boolean
Example: event.isAfter(range). Returns true when the event begins strictly after the supplied temporal value ends.
Parameters
- other: TemporalLike
Returns boolean
- Defined in packages/core/src/Event.ts:212

isBefore

isBefore(other: TemporalLike): boolean
Example: event.isBefore(range). Returns true when the event ends strictly before the supplied temporal value begins.
Parameters
- other: TemporalLike
Returns boolean
- Defined in packages/core/src/Event.ts:207

key

key(): K
Example: event.key(). Returns the event key.

Returns K
- Defined in packages/core/src/Event.ts:54

merge

merge<U extends object>(patch: U): Event<K, Readonly<D & U>>
Example: event.merge({ host: "api-1" }). Returns a new event with a shallow payload merge applied.
Type Parameters
- U extends object
Parameters
- patch: U
Returns Event<K, Readonly<D & U>>
- Defined in packages/core/src/Event.ts:87

overlaps

overlaps(other: TemporalLike): boolean
Example: event.overlaps(range). Returns true when the event extent overlaps the supplied temporal value.
Parameters
- other: TemporalLike
Returns boolean
- Defined in packages/core/src/Event.ts:197

rename

rename<const Mapping extends Partial<{ [K in string]: string }>>(
    mapping: Mapping,
): Event<
    K,
    Readonly<
        {
            [Name in string as Name extends keyof Mapping
                ? Mapping[Name] extends string ? any[any] : Name
                : Name]: D[Name]
        },
    >,
>
Example: event.rename({ cpu: "usage" }). Returns a new event with payload fields renamed according to the supplied mapping.
Type Parameters
- const Mapping extends Partial<{ [K in string]: string }>
Parameters
- mapping: Mapping
Returns Event<
    K,
    Readonly<
        {
            [Name in string as Name extends keyof Mapping
                ? Mapping[Name] extends string ? any[any] : Name
                : Name]: D[Name]
        },
    >,
>
- Defined in packages/core/src/Event.ts:106

select

select<const Keys extends readonly (keyof D)[]>(
...keys: Keys,
): Event<K, Readonly<Pick<D, Keys[number]>>>
Example: event.select("cpu", "healthy"). Returns a new event containing only the selected payload fields.
Type Parameters
- const Keys extends readonly (keyof D)[]
Parameters
- ...keys: Keys
Returns Event<K, Readonly<Pick<D, Keys[number]>>>
- Defined in packages/core/src/Event.ts:95

set

set<Field extends string | number | symbol>(
field: Field,
value: D[Field],
): Event<K, D>
Example: event.set("value", 2). Returns a new event with one payload field replaced.
Type Parameters
- Field extends string | number | symbol
Parameters
- field: Field
- value: D[Field]
Returns Event<K, D>
- Defined in packages/core/src/Event.ts:79

timeRange

timeRange(): TimeRange
Example: event.timeRange(). Returns the event extent as a TimeRange.

Returns TimeRange
- Defined in packages/core/src/Event.ts:179

trim

trim(other: TemporalLike): Event<K, D> | undefined
Example: event.trim(range). Returns a new event clipped to the supplied temporal value, if the event overlaps it.
Parameters
- other: TemporalLike
Returns Event<K, D> | undefined
- Defined in packages/core/src/Event.ts:222

type

type(): K["kind"]
Example: event.type(). Returns the underlying key kind.

Returns K["kind"]
- Defined in packages/core/src/Event.ts:64

withKey

withKey<NextKey extends EventKey>(key: NextKey): Event<NextKey, D>
Example: event.withKey(new Time(Date.now())). Returns a new event with the same payload and a different key.
Type Parameters
- NextKey extends EventKey
Parameters
- key: NextKey
Returns Event<NextKey, D>
- Defined in packages/core/src/Event.ts:59

Class Event<K, D>

Example

Type Parameters

Index

Constructors

Methods

Constructors

constructor

Type Parameters

Parameters

Returns Event<K, D>

Methods

asInterval

Parameters

Returns Event<Interval, D>

Parameters

Returns Event<Interval, D>

asTime

Parameters

Returns Event<Time, D>

asTimeRange

Returns Event<TimeRange, D>

begin

Returns number

collapse

Type Parameters

Parameters

Returns Event<K, Readonly<Omit<D, Keys[number]> & Record<Name, R>>>

Type Parameters

Parameters

Returns Event<K, Readonly<D & Record<Name, R>>>

contains

Parameters

Returns boolean

data

Returns Readonly<D>

end

Returns number

get

Type Parameters

Parameters

Returns Readonly<D>[Field]

intersection

Parameters

Returns TimeRange | undefined

isAfter

Parameters

Returns boolean

isBefore

Parameters

Returns boolean

key

Returns K

merge

Type Parameters

Parameters

Returns Event<K, Readonly<D & U>>

overlaps

Parameters

Returns boolean

rename

Type Parameters

Parameters

Returns Event< K, Readonly< { [Name in string as Name extends keyof Mapping ? Mapping[Name] extends string ? any[any] : Name : Name]: D[Name] }, >,>

select

Type Parameters

Parameters

Returns Event<K, Readonly<Pick<D, Keys[number]>>>

set

Type Parameters

Parameters

Returns Event<K, D>

timeRange

Returns TimeRange

trim

Parameters

Returns Event<K, D> | undefined

type

Returns K["kind"]

withKey

Returns Event<
K,
Readonly<
{
[Name in string as Name extends keyof Mapping
? Mapping[Name] extends string ? any[any] : Name
: Name]: D[Name]
},
>,
>