Tilemap objects property is not always an array (as it is typed)

[robbeman]

When only empty object layers are added in Tiled, this is an empty object instead of an empty array.

https://github.com/photonstorm/phaser/blob/1a086fc57c8faa53885fd1a4e20d617b958d3677/src/tilemaps/Tilemap.js#L260

Suggested solution:

  this.objects = Array.isArray(mapData.objects) ? mapData.objects : [];

Maybe a little short-sighted? On the other hand, my game crashed because I relied on the type comment.

[photonstorm]

Thank you for submitting this issue. We have fixed this and the fix has been pushed to the master branch. It will be part of the next release. If you get time to build and test it for yourself we would appreciate that.