MapLibre GL JS v5 → v6 Migration

Use this only when the question, or the code in it, involves one of the seven changes below. For any other MapLibre question, such as sources, layers, styling or terrain, write the answer with v6 imports and add no section, table, list or note about v6 changes or migrating from v5.

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 for code that touches one of these seven, the natural-sounding answer is usually the v5 one, 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 ERR_PACKAGE_PATH_NOT_EXPORTED, 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

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".