Function deleteAll

deleteAll(json?): void
Delete all objects of a given type.
Parameters
- json: {
  type: string;
  } = ...
  - type: string
    the type of object to delete, routes, markers, tracks, or all
Returns void
Example
```
{"type": "routes"}  // delete all routes

{"type": "all"}  // delete all routes, markers, and tracks
```