Function ensureLayersAreVisible

ensureLayersAreVisible(layerIds): void
JMap.Layer.ensureLayersAreVisible

Make sure that all specified layers are visible on the Map. All parent layers of all Layers will also be made visible
Parameters
- layerIds: JId[]
  An array of JMap layer ids
Returns void
Example
```
// show layer ids 5, 6 and 7 (and all parent layers)
JMap.Layer.ensureLayersAreVisible([5, 6, 7])
```