PortalJS — Add Map

Overview

Add an interactive Leaflet map as a view on a dataset's showcase in a portaljs-catalog portal. The skill installs react-leaflet/leaflet (added directly — never @portaljs/components), writes a reusable Map component split across MapView.tsx (the Leaflet code) and Map.tsx (a dynamic(..., { ssr: false }) wrapper, since Leaflet touches window at module load), and renders <Map /> into the Views section of the showcase route pages/[owner]/[slug].tsx for one chosen GeoJSON dataset. The dataset should already carry format: "geojson" in datasets.json; if it doesn't exist yet, the skill can copy the file and register it first.

Prerequisites

• A scaffolded PortalJS portal (see portaljs-new-portal).
• The target dataset registered in datasets.json with format: "geojson" (see portaljs-add-dataset), or a GeoJSON source file/URL to register.
• Node 18+ and npm available in the portal directory.

Instructions

The canonical, full step-by-step workflow is .claude/commands/portaljs-add-map.md — the single source of truth. Read and follow it when executing. Summary:

1. Gather input — dataset slug (or a GeoJSON source to register), portal directory. If any is missing, interview the user; never dead-end on a missing value.
2. Validate the portal directory (datasets.json, package.json, pages/[owner]/[slug].tsx must exist).
3. Resolve the dataset from datasets.json, or validate and register a new GeoJSON source (copy to /public/data/, append a manifest entry).
4. Install map dependencies: npm install react-leaflet@^5 leaflet@^1.9 and npm install -D @types/leaflet (skip if already present).
5. Write components/MapView.tsx and components/Map.tsx (idempotent — skip if Map.tsx already exists).
6. Render <Map /> into the Views section, gated on the dataset's (namespace, slug) so other showcases are unaffected. Extend an existing view-dispatch block, do not overwrite it.
7. Verify with npx tsc --noEmit (never next build against a live dev server).
8. Report the component, route, and dependency added.

Output

• Created: components/MapView.tsx and components/Map.tsx (Leaflet wrapper, if absent); public/data/<slug>.geojson (only when registering a new dataset).
• Modified: pages/[owner]/[slug].tsx (import + gated <Map /> in Views); datasets.json (only when registering a new dataset); package.json (react-leaflet, leaflet, @types/leaflet).
• Verified: npx tsc --noEmit passes.
• Result: the map renders at /@<namespace>/<slug> under a "Views" heading.

Error Handling

Symptom	Cause	Fix
Dataset not found or not GeoJSON	Slug missing from datasets.json or format is tabular	List GeoJSON datasets and re-prompt; suggest portaljs-add-chart for tabular data.
Source fetch/copy fails	URL returns non-200 or local path missing	Report the HTTP status or missing path; ask for a corrected source.
"Not valid GeoJSON"	Parsed JSON type isn't a Feature/geometry type	Tell the user and point to portaljs-add-dataset for tabular data.
tsc failure	Bad import path or gating condition	Fix the first reported error before reporting success.
Map appears on every dataset	View not gated on (namespace, slug)	Wrap the <Map /> render in the dataset check shown in the Instructions.
Features render in the wrong place	Data isn't WGS84 (EPSG:4326) lon/lat	Reproject the source data to WGS84 before adding.
Slow render	Thousands of features in one file (>5MB)	Simplify geometries (e.g. mapshaper) before adding.

Examples

Example 1 — Map an already-registered dataset

/portaljs-add-map dataset=park-boundaries

Example 2 — Register a local GeoJSON file and map it

/portaljs-add-map source=./data/bike-routes.geojson slug=bike-routes name="Bike Routes"

Example 3 — Register a remote GeoJSON URL and map it

/portaljs-add-map source=https://example.com/districts.geojson slug=districts namespace=reference

Resources

• Full workflow: .claude/commands/portaljs-add-map.md
• Map props and troubleshooting reference: references/reference.md
• Related skills: portaljs-add-dataset, portaljs-add-chart, portaljs-define-schema
• react-leaflet documentation: https://react-leaflet.js.org/