@finchart/dom

The browser shell for @finchart/core — what react-dom is to react.

Install

pnpm add @finchart/dom @finchart/core

@finchart/core is a peer — install both.

Core knows nothing about the DOM, at runtime or in its types. Everything you need to stand a chart up in a browser is here:

• Assembly — browserDeps(options) returns a recipe ((container) => PlotDeps), and PlotBuilder.create(...).build(el) feeds it the element to finish the wiring. Every binding to the DOM happens at that assembly step.
• Implementations — DOM layers (createDomLayers), DOM axis labels, pane separators, pointer input (pan, zoom, pinch, keyboard), the CSS variable reader, and size observation.
• DOM overlay extensions — legend() and tooltip(). They live here because they render into an overlay rather than onto the canvas.

<div id="chart" style="height: 400px"></div>

import { candleSeries } from "@finchart/core";
import { PlotBuilder, browserDeps } from "@finchart/dom";

const plot = PlotBuilder.create(browserDeps({ autoSize: true }), candleSeries())
  .addDataPoints(data)
  .build(document.getElementById("chart")!);

The container needs a size from CSS — the canvas is layered over it rather than laid out in it, so an empty <div> stays 0 px tall and the content after it is drawn over. With autoSize the chart follows that size; without it the canvas keeps the builder's setSize, so give the container the same height.

Headless consumers (servers, workers, tests) don't install this package — createPlotModel from @finchart/core is all they need.

Touch and trackpad

The chart takes horizontal gestures and leaves vertical ones to the page: the container is touch-action: pan-y, so a vertical swipe over a chart that sits in a scrolling page scrolls the page. What that gives up on touch is dragging the value axis vertically; a mouse is unaffected.

The wheel zooms by how far it moves — zoomSpeed per 100 px, the length of one mouse notch, so a trackpad's stream of small deltas zooms as gently as it scrolls — and a mostly sideways swipe pans instead. By default it takes every wheel event, which means a trackpad's two-finger scroll zooms the chart instead of scrolling the page. On a page with content around the chart, gate it on a modifier:

browserDeps({ pointer: { wheel: "modifier" } });

Then a plain wheel or two-finger scroll reaches the page, and Ctrl + wheel zooms — which is how Chromium, Firefox and WebKit encode a trackpad pinch, so pinching still zooms. ⌘ + wheel is accepted as a shortcut as well.

When the pointer leaves the chart (or the browser takes over a touch gesture), the crosshair is cleared: the crosshair event fires once with null, and the tooltip and legend follow it.

A series that describes itself gets its own rows — a candle reads SOXL: O 105.75 H 106.10 L 104.90 C 105.30 V 800 in the tooltip (SOXL O … in the legend) instead of one close. formatValue still formats every plain value; give formatRow ((value, { label, sample }) => string) to read a row by its label, so V can be a volume and not a price.

Support matrix

For screen-reader access to exact values, dataTable mounts an expandable native table beside the chart. Pass it a target outside the chart's role="img", a series read() getter, a caption, and value columns. The trading example shows the complete wiring.

• Node 20.19+ — where the headless path (SSR, workers, tests) runs; CI runs that floor.
• Browsers — Chrome 98+ · Edge 98+ · Firefox 94+ · Safari 15.4+ (2022-03). The floor is set by structuredClone, Object.hasOwn, and Array.prototype.at, and no polyfills ship — bring your own if you need to support something older. CI runs current Playwright Chromium, Firefox, and WebKit. The historical floor versions and branded Edge/Safari are not separately exercised.
• The repository's own toolchain (Node 24.21+ · pnpm 12) is higher than this. That is the contributor's floor, not the consumer's.

Docs

• Style tokens — the full CSS variable table — theme.md
• The Plot contract — plot-contract.md
• Glossary — glossary.md
• Time zones and sessions — time-zones.md