Function update

update(contextId, params?): Promise<JMapContext>
JMap.MapContext.update

Updates a map context, saves the current map context data.

The map-context update is persisted server-side.

You can provide partial meta-data (= data that describes the context), if a meta-data is not provided, it will not be changed.
Parameters
- contextId: JId
  the JMap map context id
- Optional params: JMapContextMetaData
  partial map context meta-data, only data provided will be updated
Returns Promise<JMapContext>
the updated map context
Throws
if context not found, or empty or invalid meta-data, or server request error

Example
```
// update the map-context id=3
JMap.MapContext
   .update(3, { title: "My new title" }) // only "title" meta-data will be changed, "description" and "shareLink" keep the same
   .then(mapContext => console.info(`Map context id=3 meta-data and map data updated.`, mapContext))
   .catch(error => console.error(error))
```