Telemetry

Telemetry records a property's value over time, such as a project's progress or a sensor's readings. The object exposes the latest value while the full history remains available to query.

Define a telemetry property

Add mode: "telemetry" to a property:

import { prop } from "@sixb/core/ontology"

prop("progress", "integer", { mode: "telemetry" })

Include this property in your object type's properties array.

Append a point

Select an existing object and its telemetry property, then provide the value and the time of the reading as a Date:

import { Project } from "./ontology/project"

const progress = sixb.objects(Project).byId("proj-001").telemetry(Project.p.progress)

await progress.append({
  value: 45,
  at: new Date("2026-09-01T12:00:00Z"),
})

The object must exist before you append. Writing to the same object, property, and timestamp replaces that point. An older reading adds to the history without replacing a newer reading as the object's latest value.

Read history

Use history() to read points within a time range. Results contain { value, at, unit? } and arrive oldest first unless you pass order: "desc". Both time bounds are inclusive:

const points = await progress.history({
  from: new Date("2026-09-01T00:00:00Z"),
  to: new Date("2026-09-07T23:59:59Z"),
  limit: 100,
})

To read the latest point with its timestamp, request one point in descending order. An empty series returns an empty array:

const [latest] = await progress.history({ order: "desc", limit: 1 })

Append in batch

Use appendTelemetryBatch() to record values for several objects of the same type. Each item can contain multiple telemetry properties. Its optional at applies to every property in that item and defaults to the current time:

await sixb.objects(Project).appendTelemetryBatch([
  { id: "proj-001", properties: { progress: 45 } },
  { id: "proj-002", properties: { progress: 70 } },
])

To import readings from a dataset, use a telemetry projection.

Values with units

For a property with a quantitative semanticType, include a valid unit with each point. Properties without a semantic type do not accept units. See Units.

await sixb.objects(Project).byId("proj-001").telemetry(Project.p.timeSpent).append({
  value: 2,
  unit: "hour",
  at: new Date("2026-09-01T12:00:00Z"),
})