getFlatLayersArray() throws error

[silvester-pari]

The helper function getFlatLayersArray() sometimes fails since layers sometimes seems to be undefined and therefore can't be spread at:

EOxElements/elements/map/src/layer.ts

Line 27 in 94eff0c

flatLayers.push(...layers);

Uncaught (in promise) TypeError: layers is not iterable (cannot read property undefined)

[RobertOrthofer]

The doc of the method is wrong, the getFlatLayersArray is meant as a convenience-functionality to flatten the given layers, not all layers of the map.

To get all layers of the map, the correct syntax would be

eoxMap.getFlatLayersArray(eoxMap.map.getAllLayers())

[silvester-pari]

Aah, that explains it! In that case, I'd propose to offer this functionality in a different way, since it probably doesn't make too much sense offering it as a property of the eox-map.

I propose to export it in the main file (e.g. export { getFlatLayersArray }) and expand the description in layer.ts to:

/**
 * Returns a flat array of provided layers, including groups
 * To get all layers without groups, you can use the native
 * OL `getAllLayers` method on the map itself:
 * https://openlayers.org/en/latest/apidoc/module-ol_Map-Map.html#getAllLayers
 * 
 * @param layers layers Array
 * @example getFlatLayersArray(eoxMap.map.getAllLayers())
 */

This needs adaptations in e.g. tests and is generally a breaking change, so moving this to v2 milestone.

Although we could add this now in an v1.x update, and deprecate the property with v2.

[silvester-pari]

The docs have been updated (a053bbb); for the general topic about exporting convenience functions, a new issue has been created: #1177