Diagram Boundary
Svelvet now has an optional
  boundary that users can implement into their diagrams! To access this feature,
  pass the boundary prop to your
  Svelvet
  application and set it equal to an object. Give the
  boundary
  object an x and
  y
  key and set their values to a
  positive
  number. The x and
  y
  properties represent the width and height of your
  boundary
  and will create a boundary
  starting from 0 to the number
  specified. Do not set node positions to negative values while using the
  boundary feature.
Implementing Diagram Boundaries
Click here for a sandbox, or test it out below!