Function isLinkShared

isLinkShared(contextId): boolean
JMap.MapContext.isLinkShared

Returns true if the map context is shared, for a given map context id.
Parameters
- contextId: JId
  the JMap map context id
Returns boolean
Throws
if map-context not found

Example
```
// returns true if the map-context id=3 is shared
JMap.MapContext.isLinkShared(3)
```