Update generation code for the specific case of geojson (#463)

* Update generation code for the specific case of geojson

* Update changelog

* Fix type to match maplibre-gl

* Remove unwanted console.log

* Fix lint

* Update CHANGELOG.md

Co-authored-by: Bart Louwers <bart.louwers@gmail.com>

---------

Co-authored-by: Bart Louwers <bart.louwers@gmail.com>

CHANGELOG.md

@@ -1,19 +1,30 @@
 ## main
 
+### ✨ Features and improvements
+
 * Add back `migrate`, `validate` and `format` to the exported methods of this package
 * Add terrain to diff method and improve type. This also removes the `operations` from the API [#460](https://github.com/maplibre/maplibre-style-spec/pull/460)
+* Improve the type of `data` in the `GeoJSONSourceSpecification` for TypeScript.
 
 ## 19.3.3
+
+### ✨ Features and improvements
+
 * Improve types for feature to include `unknown` [#365](https://github.com/maplibre/maplibre-style-spec/pull/365)
 * Improve sprite documentation and supported versions [#390](https://github.com/maplibre/maplibre-style-spec/pull/390)
 
 
 ## 19.3.2
+
+### ✨ Features and improvements
+
 * Add raster dem source `redFactor`, `greenFactor`, `blueFactor`, `baseShift` properties [#326](https://github.com/maplibre/maplibre-style-spec/issues/326)
 * Improve error messages around `hillshade` layers not using `raster-dem` sources [#353](https://github.com/maplibre/maplibre-style-spec/pull/353)
 
 ## 19.3.1
 
+### ✨ Features and improvements
+
 * Document `raster-fade-duration` property's effect on rendering a video. [#297](https://github.com/maplibre/maplibre-style-spec/pull/297)
 * Add and expose `isZoomExpression`. [#267](https://github.com/maplibre/maplibre-style-spec/issues/267)
 

build/generate-style-spec.ts

@@ -314,7 +314,14 @@ ${objectDeclaration('LightSpecification', spec.light)}
 
 ${objectDeclaration('TerrainSpecification', spec.terrain)}
 
-${spec.source.map(key => objectDeclaration(sourceTypeName(key), spec[key])).join('\n\n')}
+${spec.source.map(key => {
+        let str = objectDeclaration(sourceTypeName(key), spec[key]);
+        if (sourceTypeName(key) === 'GeoJSONSourceSpecification') {
+        // This is done in order to overcome the type system's inability to express this type:
+            str = str.replace(/unknown/, 'GeoJSON.GeoJSON | string');
+        }
+        return str;
+    }).join('\n\n')}
 
 export type SourceSpecification =
 ${spec.source.map(key => `    | ${sourceTypeName(key)}`).join('\n')}