Files
scalesApp/.claude/agent-memory/react-expert-dev/MEMORY.md
T
gitea 122480cd46 Add the A4 report designer and fix band layout
Brings in the A4 (millimetre) report designer alongside the existing
matrix editor, migrates the frontend from react-scripts to Vite/Vitest,
and fixes four defects found while using the A4 band tools.

Layout — layout.js now implements the standard banded-report model:
everything prints where it was drawn, and a band growing per data row is
the only thing that moves anything. Previously `paginate` re-flowed every
band from the top margin, so a band placed halfway down the page
previewed at the top, and `header` was treated as a page header and
hoisted above the statics drawn before it. A header is a COLUMN header:
it prints in place and repeats only on a continuation page. Statics now
take part too — one drawn below a band keeps its drawn gap as that band
grows, and follows onto the next page rather than vanishing when pushed
past the bottom margin. The displacement is keyed on the band's design
bottom, not on an instance's laid-out y: every row of a band shares one
design position, so keying on the instance measured the gap from row 1
and let the static overlap rows 2..n.

Band children — a child's x is relative to its band, as its y already
was. layout() emitted it raw, so a field printed measured from the paper
edge instead of the band's left margin. Instances now carry bandX.

Band placement — a band's x comes from the page margins, so creation
takes only the click's Y (the factory's x was being overwritten by the
spread order) and dragging is locked to the vertical axis. Bands render
as a strip, with top/bottom rules only, matching the matrix editor.
fromApiReport reflows on load so reports saved with a stray x straighten
themselves. Matrix bands are constrained to vertical too.

Drag lifecycle — useElementDrag re-subscribed its document listeners on
every render during a drag, because the effect depended on an unmemoized
onDrag. Each re-subscribe removed the mouseup listener before adding the
next, measured as add/remove/add/remove/add across two mousemoves, and a
release landing in that gap was lost: the element kept following the
cursor until the next click. Snapping made it routine, since a held
guide stops x/y changing and leaves the guide overlay's render sitting
between the move and the release. onDrag and dragData now go through
refs so the effect depends on [isDragging] alone.

Note: the matrix editor has no test coverage, so its band constraint is
verified by reading only. The A4 suite is 201 passing tests.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-09-20 12:52:20 +03:00

4.2 KiB

ScalesApp React Expert Memory

Key File Paths

  • Report Editor root: frontend/src/components/ReportEditor/
  • Element models: models/Element.jsx — OOP class hierarchy, fromJSON has elementClasses map
  • Element CSS: elements.css — one block per element type
  • Inspector CSS: ObjectInspector.css
  • Data resolver utils: utils/dataResolver.js — resolveDBTextValue, getAvailableObjects, getAvailableFields
  • Expression evaluator: utils/expressionEvaluator.js — recursive-descent, no eval
  • A4 designer (sibling tree, mm-based): frontend/src/components/ReportEditor/a4/

Two editors, deliberately duplicated

The matrix editor (EditorCanvas.jsx, models/Element.jsx, ResizeHandles.jsx, ObjectInspector.jsx, ReportEditor.jsx) is treated as frozen. The A4 designer under a4/ copies similar logic rather than extracting shared abstractions — per the plan at .claude/plans/a4-report-designer.md. Do not "DRY up" the two; the duplication is the point.

Key unit difference: matrix bounds are inclusive (x + width - 1); A4 bounds in a4/geometry.js are exclusive (a 40mm box at x=10 has right edge 50).

Safely reusable by both: hooks/useElementDrag.jsx (emits raw pixel deltas, snapping left to the consumer), hooks/useElementSelection.jsx, DataContext, BandContext.

Element Type Pattern (matrix editor)

Adding a new element type requires touching 8 files:

  1. models/Element.jsx — new class + register in elementClasses map in fromJSON
  2. NewElement.jsx — component file, modeled on DBTextField.jsx
  3. ExpressionEditorPanel.jsx (or equivalent inspector panel)
  4. EditorCanvas.jsx — import + renderElement case + click handler in handleCanvasClick
  5. Toolbar.jsx — tool button
  6. ObjectInspector.jsx — import panel + render for element.type === 'xxx'
  7. elements.css — CSS block for new class
  8. ResizeHandles.jsx — add type to getHandles switch, getHandlePosition branch, and resize logic branch

ObjectInspector Band-Detection Pattern

When a panel needs to detect if an element is inside a band (for field resolution):

const parentBand = allElements.find(el => el.type === 'band' && el.children && el.children.includes(element.id));
// Nested band handling:
if (parentBand.parentBandId) {
  const grandparentBand = allElements.find(el => el.id === parentBand.parentBandId);
  // grandparentData[0][parentBand.dataSource] → nestedData array
}

DBTextField / ExpressionField Props Pattern

Both receive: element, isSelected, isSingleSelection, onSelect, onUpdate, onDelete, onDragStart, onDrag, charWidth, charHeight, previewMode, toolMode, parentBandId

Uses hooks: useElementDrag, useElementSelection, useReportData, useBandContext

resolveDBTextValue signature

resolveDBTextValue(reportData, objectKey, fieldPath, parentBandId, { currentBandData })
  • objectKey = '' for band-relative field access

ExpressionField Field Ref Format

[objectKey.fieldPath] for top-level fields, [fieldPath] for band-relative fields. Strip brackets, split on first . to get objectKey and fieldPath.

Build tooling

Vite + Vitest (no CRA/Jest). npm run dev / npm start → port 5172; npm test → vitest run; npm run build → frontend/build/. Config: frontend/vite.config.mjs. Env vars are import.meta.env.VITE_*. Any new production file containing JSX must be named .jsx — a .js file with JSX passes tests and the dev server but fails vite build. See vite-vitest-migration.

Detailed notes