uneri

DuckDB-wasm + uPlot time-series charting library for real-time streaming data.

Generic schema-driven design: define columns and derived SQL expressions, and uneri handles DuckDB ingestion, query-time downsampling, and chart rendering.

Build

pnpm install
pnpm build

Test

pnpm test        # vitest unit tests (59 tests)
pnpm test:e2e    # Playwright E2E tests (5 tests)

Examples

sine-wave

Basic real-time sine/cosine visualization.

pnpm example:sine-wave

Open http://localhost:5174

mixed-density

Mixed-density data test: sparse overview (100 points over 5000s) + dense streaming (100 msg/sec). Used for E2E testing of the time-bucket downsampling algorithm.

pnpm example:mixed-density

Open http://localhost:5175

Architecture

• IngestBuffer<T> — staging buffer with drain pattern (decouples WebSocket arrival from DuckDB insertion)
• useDuckDB(schema) — initializes DuckDB-wasm, creates table
• useTimeSeriesStore(options) — tick loop: drain buffer → INSERT → periodic query with downsampling
• TimeSeriesChart — uPlot wrapper with programmatic update guard
• buildDerivedQuery(schema, tMin, maxPoints) — time-bucket downsampling SQL
• sliceArrays / lowerBound / upperBound — binary search viewport clipping