@molecule/app-charts-chartjs

Auto-generated, AI-first package reference for the molecule.dev ecosystem. It is written to be read by coding agents as much as by people, and is generated from this package's source — edit src/index.ts JSDoc, not this file.

@molecule/app-charts-chartjs — a Chart.js-backed provider for the @molecule/app-charts charting interface. Bond it once at startup and every createLineChart / createBarChart / … call renders a REAL chart (the built-in default provider only paints a "no provider bonded" placeholder).

Quick Start

import { setProvider, createLineChart } from '@molecule/app-charts'
import { provider } from '@molecule/app-charts-chartjs'

setProvider(provider) // wire ONCE at app startup, before any create*Chart call

// In a component (React ref + effect), destroy on cleanup:
const chart = createLineChart(canvasEl, {
  labels: ['Jan', 'Feb', 'Mar'],
  datasets: [{ label: 'Revenue', data: [12, 19, 8] }],
})
// …later: chart.destroy()

Type

provider

Installation

npm install @molecule/app-charts-chartjs @molecule/app-charts chart.js

API

Functions

createProvider()

Creates a Chart.js-backed ChartProvider.

function createProvider(): ChartProvider

Returns: A ChartProvider that renders real charts via Chart.js.

Constants

provider

The default Chart.js chart provider, ready to bond with setProvider(provider).

const provider: ChartProvider

Core Interface

Implements @molecule/app-charts interface.

Bond Wiring

Setup function to register this provider with the core interface:

import { setProvider } from '@molecule/app-charts'
import { provider } from '@molecule/app-charts-chartjs'

export function setupChartsChartjs(): void {
  setProvider(provider)
}

Injection Notes

Requirements

Peer dependencies:

• @molecule/app-charts ^1.0.1

Runtime Dependencies

• @molecule/app-charts
• chart.js

Renders line/bar/pie/doughnut/area/scatter/bubble/radar/polar natively. area is a line chart with fill: true; polar maps to Chart.js polarArea. The remaining molecule chart types (heatmap/treemap/funnel/gauge/candlestick) are NOT in base Chart.js — createChart throws an actionable error for them (add a Chart.js plugin, or use a different provider) rather than mis-rendering.

ALWAYS destroy() the returned ChartInstance on unmount — Chart.js attaches canvas + resize listeners, so a chart left undestroyed leaks and re-creating on the same canvas throws "Canvas is already in use".

BROWSER-ONLY: it draws to a <canvas> and pulls in Chart.js (DOM). Import + wire it from app/client code, never server code.

E2E Tests

Integration checklist — drive the real UI (live preview, no mocks), adapt each item to this app's actual screens/flows, and check every box off one by one. A box you can't check is an integration bug to fix — not a skip:

• Every chart on the app's screens renders with real data — no blank canvas, no NaN/undefined axis labels.
• Plotted values match the data: spot-check at least one point/bar/slice against a number you can verify elsewhere in the UI.
• Charts update when their inputs change (date range, filter, or a newly created record that should appear).
• An empty dataset renders an empty state or zeroed axes — not a crash or a stale chart from previous data.
• Tooltips and legends (where enabled) show the correct labels and values on hover.
• Resizing the window/panel keeps charts legible (no overflow, no zero-height canvas).