@vue-data-grid/engine

@vue-data-grid/engine

Headless table core for Vue 3. It models columns (declaration, groups, order, widths, pinning, hiding, group collapse and sort state), keeps that state in a store of your choice, and turns it into geometry: flex, position: sticky and CSS custom properties. It also windows rows and columns, and ships optional composables for work on rows and cells: sorting, streaming updates, grouping with aggregates, trees, selection, cell focus, cell ranges, editing with undo, paste and fill, recent cell changes and CSV.

There is no markup here: no components, no templates, no h() calls, no render types. The engine gives you a TableScope, and your own markup renders the table from it. It is the low-level layer: @vue-data-grid/core, the main package, builds on it with the render fields of columns, keyboard navigation, autosize from content and more.

Install

pnpm add @vue-data-grid/engine vue

Vue 3.5 or later is a peer dependency. The package is ESM-only and free of side effects.

Quick start

import { defineComponent, h, shallowRef } from 'vue';
import {
	defineColumn,
	defineColumns,
	getCellText,
	createTableScopeContext,
	useTableEngine,
	useTableGeometry,
} from '@vue-data-grid/engine';

interface Instrument {
	id: string;
	symbol: string;
	price: number;
}

const column = defineColumn<Instrument>();

const columns = defineColumns({
	symbol: column(row => row.symbol, { label: 'Symbol', width: 140 }),
	price: column(row => row.price, { label: 'Price', align: 'right', format: value => value.toFixed(2) }),
});

export default defineComponent({
	props: { rows: { type: Array as () => Instrument[], required: true } },
	setup(props) {
		const root = shallowRef<HTMLElement | null>(null);

		const engine = useTableEngine({
			columns,
			rows: () => props.rows,
			root,
			rowKey: 'id',
			rowHeight: 36,
			virtual: true,
		});

		createTableScopeContext(engine.scope);
		useTableGeometry(root, engine.layers);

		return () => h('div', { ref: root, style: 'overflow: auto; height: 400px' }, [
			h('div', { style: { position: 'relative', height: `${engine.totalSize.value}px` } },
				engine.items.value.map((item) => {
					const row = engine.scope.rows.value[item.index];

					return h('div', {
						key: item.key,
						'data-dg-index': item.index,
						style: { display: 'flex', position: 'absolute', top: `${item.start}px`, height: `${item.size}px` },
					}, engine.scope.renderedColumns.value.map(rendered => h('div', rendered.cellProps,
						rendered.column ? getCellText(rendered.column, row) : undefined)));
				})),
		]);
	},
});

A real table also renders a header from headerProps, handles gestures and memoizes rows. The core styles only the geometry of a cell: its width, grow factor and pin. align becomes a data-dg-align attribute, and the layout of a cell, alignment included, comes from CSS: the structural styles of @vue-data-grid/core (@vue-data-grid/core/style.css), or rules of your own on [data-dg-column] and [data-dg-align]. Without them the price column above is not right-aligned. The documentation site in docs/ documents @vue-data-grid/core, which re-exports this core: its core page maps the exports, and a guide on your own markup renders a table from the engine. Run it with pnpm docs from the repository root. Every export carries JSDoc with the details.

Service columns and row headers

A column holds data of the row unless it says kind: 'service': a checkbox, a row number, actions. Service columns are real columns, pinned, resized and moved like any other, but toCsv, useCellRanges, useCellChanges and autosize in @vue-data-grid/core leave them out unless told otherwise (includeService, or naming the columns).

One column names each row for assistive technology: the first shown data column, or every column with rowHeader: true; rowHeader: false on the first data column leaves the table without one. RenderedColumn.rowHeader marks it, and the column window always renders it in its place, with spacers on both sides, so a row keeps its accessible name while scrolled sideways. Spacers are told apart by key (dg-spacer-start, dg-spacer-start-1, …); every rendered column and group cell has a key for v-for.

What the core does, and what is left to you

The engine learns about the right-hand side through insets, rows, and what must stay rendered: keepRows, keepColumns or scope.keepRendered.

Entry points

• @vue-data-grid/engine is the stable API. Everything in the guides is imported from here.
• @vue-data-grid/engine/internals exposes the building blocks useTableEngine is made of, for those who assemble their own engine. It is not covered by semver: signatures there change together with the engine, including in minor releases. Nothing from the root entry is repeated there.

Source layout

src/
	persist/        stores and usePersistedState: keeping any state between visits
	columns/        column declaration, order, layout, header sort, column state
	column-groups/  column groups: declaration, header rows, collapse
	engine/         useTableEngine and TableScope; column reconciliation, fit, resize
	virtual/        row and column windows, scrolling, viewport
	render/         what markup uses: CSS variables, cell styles
	rows/           row pipeline: sorting, streaming, grouping with aggregates, trees, selection, row keys
	cells/          cell addresses, focus, ranges, editing, history, paste, fill, cell changes, CSV
	shared/         stableComputed, the model ref, the row token

A folder is a feature: it holds both the pure logic and the composable on top of it. Reactivity lives only in use-* files. The other files never call ref, computed or watch, so they can be tested with plain function calls. The one exception is shared/stable-computed.ts, which is itself a reactive primitive.

Each folder has an index.ts with everything it exports to its neighbours and to the entry points. The root index.ts and internals.ts export only from those barrels, and tests/entries.spec.ts checks that every folder export lands in exactly one entry point.

Folders depend on each other in one direction only, by layers: shared, persist ← columns ← render, rows ← column-groups, virtual ← engine ← cells. A folder imports only folders of lower layers, and tests/folders.spec.ts fails on anything else, so any folder can be moved into a package of its own.

Tests

Run pnpm test from the repository root. tests/ mirrors src/.