[@types/leaflet] geoJSON() complains about arrays while documentation states they are valid

[ma7moudat]

Discussed in #60818

^{Originally posted by ma7moudat June 15, 2022}
The official Leaflet documentation states:

GeoJSON objects may also be passed as an array of valid GeoJSON objects.

However, when using Typescript, it complains when an array is passed to geoJSON():

import {geoJSON} from "leaflet";
import {LineString} from "geojson";

const myLines: LineString[] = [{
  "type": "LineString",
  "coordinates": [[-100, 40], [-105, 45], [-110, 55]]
}, {
  "type": "LineString",
  "coordinates": [[-105, 40], [-110, 45], [-115, 55]]
}];

// this cuases an error, eventhough it shouldn't:
// TS2345: Argument of type 'LineString[]' is not assignable to parameter of type 'GeoJsonObject'. 
// Property 'type' is missing in type 'LineString[]' but required in type 'GeoJsonObject'.
geoJSON(myLines);

// this works, but should not be needed
const myLinesLayer = geoJSON(undefined)
myLines.forEach((line) => myLinesLayer.addData(line))

[someonewithpc]

Fixed by #61339

[asamad-hitachi]

Hi
I am facing similar issue
I raised it to react-leaflet but they suggested to raise it here.

Issue link : https://github.com/PaulLeCam/react-leaflet/issues/1015#issue-1331955818

Please provide me any suggestions to what I should do to resolve this.
It would be great help.

[ma7moudat]

@asamad-hitachi until you get the fix, you can create a leaflet.d.ts file in your project with the following content:

// fix leaflet's geoJSON type definition
// todo remove after github issue has been resolved
// @see https://github.com/DefinitelyTyped/DefinitelyTyped/issues/60930
import { GeoJsonObject } from 'geojson'
import { GeoJSON } from 'leaflet'

declare module 'leaflet' {
    function geoJSON<P = never>(
        geojson?: GeoJsonObject | GeoJsonObject[],
        options?: GeoJSONOptions<P>
    ): GeoJSON<P>
}