MapLibre GL JS v5 → v6 Migration

MapLibre GL JS v6 (released 2026-07-22) removed several things v5 code relied on: the UMD/CSP browser bundles, the default export, CommonJS support, the internal map.transform, and the MapDataEvent type. Most models' training data predates v6. So the natural-sounding answer to "how do I do X" is usually the v5 answer, and it breaks on v6.

Primary reference: the MapLibre GL JS v5→v6 migration guide. This skill adds the gaps a model tends to fill with v5-era defaults. If the guide and this skill disagree, follow the guide and report it.

When to Use This Skill

• Upgrading an existing MapLibre GL JS v5 app to v6, or debugging a map that "used to work" after a dependency update
• Writing one of the seven patterns below: a CDN <script> tag, an import statement, a require() call, a styleimagemissing handler, code that reads map.transform, a typed data/dataloading/dataabort handler, or a bundler setup (Vite, webpack, esbuild, Rspack, Rollup)
• Debugging errors like ERRPACKAGEPATHNOTEXPORTED, a blank map after a CDN update, a sprite icon that never appears, a TypeScript error naming MapDataEvent, or a worker-loading error that blocks render

Don't use this skill to pad an unrelated answer. It covers seven narrow breaking changes, not general v6 best practice. A question about sources, layers, styling, or terrain gets a normal, focused answer with no migration reminders attached.

1. CDN script tag: ESM-only now

v6 removed the UMD bundle and the separate CSP build. There's no dist/maplibre-gl.js for a plain <script src="..."> tag anymore. Only the ESM build, dist/maplibre-gl.mjs, remains, and it needs type="module".

<!-- ❌ v5 — dist/maplibre-gl.js no longer exists in v6 -->
<script src="https://unpkg.com/maplibre-gl@5/dist/maplibre-gl.js"></script>

<!-- ✅ v6 — ESM build, type="module" required -->
<script type="module">
  import maplibregl from 'https://unpkg.com/maplibre-gl@^6.0.0/dist/maplibre-gl.mjs';
  const map = new maplibregl.Map({ container: 'map', style: '...' });
</script>

Always pin an explicit major (@^6.0.0, or a specific version). Never use @latest or a bare unversioned specifier — an unpinned CDN URL breaks the page silently the moment the next major version publishes. This already happened at the v5→v6 boundary.

2. No default export — named or namespace import only

v5's import maplibregl from 'maplibre-gl' (default import) no longer works in v6.

// ❌ v5 — default export removed
import maplibregl from 'maplibre-gl';

// ✅ v6 — namespace import
import * as maplibregl from 'maplibre-gl';

// ✅ v6 — or import only what you use
import { Map, NavigationControl } from 'maplibre-gl';

This applies whether the code is new or converted from a Mapbox GL JS snippet (import mapboxgl from 'mapbox-gl'). Don't carry the default-import shape over either way.

3. No CommonJS — require('maplibre-gl') throws

maplibre-gl's package.json exports field has only an "import" condition in v6, not "require". So require('maplibre-gl') throws ERRPACKAGEPATHNOTEXPORTED in plain Node. That's expected behavior, not a bug in the caller's setup.

// ❌ throws ERR_PACKAGE_PATH_NOT_EXPORTED in v6
const maplibregl = require('maplibre-gl');

// ✅ convert the file to ESM (named/namespace import — see item 2)
import { Map } from 'maplibre-gl';

// ✅ or, if the caller must stay CommonJS, load it dynamically
const { Map } = await import('maplibre-gl');

This section is only about a bare Node require() call. If a bundler is involved (webpack, Vite, etc.) and require() still fails, that's a separate ESM-interop config issue.

4. styleimagemissing no longer resolves the request — use setMissingStyleImageResolver

In v5, listening for styleimagemissing and calling map.addImage() synchronously from the handler would supply the missing icon. In v6, styleimagemissing is notify-only. Calling addImage from the handler no longer resolves the pending request.

// ❌ v5 pattern — no longer resolves the request in v6
map.on('styleimagemissing', (e) => {
  map.addImage(e.id, generateIcon(e.id));
});

// ✅ v6 — register a resolver
map.setMissingStyleImageResolver((id) => {
  return generateIcon(id); // or return a Promise
});

Use this whenever a style references icon-image names that aren't in the sprite sheet and need to be generated or fetched at runtime.

5. map.transform is gone — use the public Camera API

v6 refactored Map to compose a Camera instead of extending it. Map now extends Evented directly and forwards the camera API. The internal map.transform property was removed as part of that change.

// ❌ v5 — reaching into the internal transform
const { zoom, bearing, pitch } = map.transform;
const center = map.transform.center;

// ✅ v6 — public accessors
const zoom = map.getZoom();
const bearing = map.getBearing();
const pitch = map.getPitch();
const center = map.getCenter();

There's no general public replacement for the raw projection/view matrix. It was never exposed on Map itself, in v5 or v6 — it only ever lived on map.transform. The one place a matrix is still available is inside a custom layer's render() callback, via the callback's arguments (CustomRenderMethodInput.getProjectionData() / defaultProjectionData; see the custom layers API). Outside a custom layer, use the public getters above. For anything else the public API doesn't expose, open an issue or PR instead of reintroducing a private accessor.

6. MapDataEvent removed — use MapSourceDataEvent / MapStyleDataEvent

v6 made every fired event a real class, instantiated per event. The old catch-all MapDataEvent type is gone. data, dataloading, and dataabort are now typed as MapSourceDataEvent | MapStyleDataEvent. A source data event carries its full source info (sourceId, tile, sourceDataType, ...) directly on its own type, instead of a generic shared shape.

// ❌ v5 — MapDataEvent no longer exists in v6
import type { MapDataEvent } from 'maplibre-gl';
map.on('data', (e: MapDataEvent) => {
  /* ... */
});

// ✅ v6 — narrow on the union MapLibre now exports
import type { MapSourceDataEvent, MapStyleDataEvent } from 'maplibre-gl';
map.on('data', (e: MapSourceDataEvent | MapStyleDataEvent) => {
  if ('sourceId' in e) {
    // MapSourceDataEvent — e.sourceId, e.sourceDataType, e.tile
  } else {
    // MapStyleDataEvent
  }
});

The same fix applies anywhere a type import or annotation names MapDataEvent, including dataloading and dataabort handlers.

7. Bundled builds still need setWorkerUrl() — CDN ESM does not

v6 changed how the source-processing worker is located, but only for bundled apps. A plain CDN <script type="module"> (item 1) auto-detects the worker URL from import.meta.url and needs no extra setup. Inside a bundler (Vite, webpack, esbuild, Rspack, Rsbuild, Rollup), import.meta.url doesn't reliably resolve to the worker file within the bundler's own module graph. Each of these setups needs one explicit setWorkerUrl() call, made once before creating the Map.

// ❌ v6 with a bundler, no setWorkerUrl() call — worker fails to load, map never renders
import { Map } from 'maplibre-gl';
const map = new Map({
  /* ... */
});

// ✅ Vite — the `?worker&url` query bundles the worker's own dependencies with it
import { Map, setWorkerUrl } from 'maplibre-gl';
import 'maplibre-gl/dist/maplibre-gl.css';
import workerUrl from 'maplibre-gl/dist/maplibre-gl-worker.mjs?worker&url';

setWorkerUrl(workerUrl);
const map = new Map({
  /* ... */
});

// ✅ Webpack 5+ (Rspack and Rsbuild use the same pattern) — call setWorkerUrl() the same way, then create the Map
import { Map, setWorkerUrl } from 'maplibre-gl';

setWorkerUrl(new URL('maplibre-gl/dist/maplibre-gl-worker.mjs', import.meta.url).toString());

In Vite, use ?worker&url, not plain ?url. The worker file imports a sibling maplibre-gl-shared.mjs, and plain ?url emits the worker verbatim without it. That makes the worker fail on its first import in production, so no vector tiles load. Esbuild, Rollup, and Turbopack need the same one-time call with their own asset-handling syntax; Next.js needs a different approach entirely. See the install guide for current per-bundler snippets — this changes with tooling versions faster than the rest of this skill.

Don't carry this into item 1's CDN case. A plain <script type="module"> import from a CDN URL never needs setWorkerUrl().

Reference

• MapLibre GL JS v5→v6 migration guide and its CHANGELOG (v6.0.0 section)
• CustomLayerInterface API docs and install guide (per-bundler setWorkerUrl() snippets)