SequenceConstraintData

// Map each item to an IComparable, in this case taken from a custom object stored in the Tag
layoutData.sequenceConstraints.itemComparables = (item) => {
  const data = item.tag
  if (data !== null) {
    return data.sequenceOrder
  }
  // Don't constrain sequencing if the tag doesn't contain our custom object.
  return null
}

// Define sequence constraints for a few nodes via a mapper. Nodes that are not
// explicitly mapped don't have constraints on their placement within the layer.
const mapper = layoutData.sequenceConstraints.itemComparables.mapper
// Place node1 before node2
mapper.set(node1, 1)
mapper.set(node2, 3)
// Place node3 between both of them
mapper.set(node3, 2)
// Place node4 after the others by assigning a larger value
mapper.set(node4, 8)
// The exact values don't matter much they just define an ordering. However, all
// values must have the same type you cannot mix int and string or double, for example.// Define sequence constraints for a few nodes via a mapper. Nodes that are not
// explicitly mapped don't have constraints on their placement within the layer.
const mapper = layoutData.sequenceConstraints.itemComparables
  .mapper as IMapper<INode, any>
// Place node1 before node2
mapper.set(node1, 1)
mapper.set(node2, 3)
// Place node3 between both of them
mapper.set(node3, 2)
// Place node4 after the others by assigning a larger value
mapper.set(node4, 8)
// The exact values don't matter much they just define an ordering. However, all
// values must have the same type you cannot mix int and string or double, for example.

layoutData.sequenceConstraints.itemComparables =
  ItemMapping.from(sequenceMapper)
// Or create the mapping from a Map, instead:
layoutData.sequenceConstraints.itemComparables =
  ItemMapping.from(sequenceMap)layoutData.sequenceConstraints.itemComparables = ItemMapping.from<
  IModelItem,
  IComparable
>(sequenceMapper)
// Or create the mapping from a Map, instead:
layoutData.sequenceConstraints.itemComparables = ItemMapping.from<
  IModelItem,
  IComparable
>(sequenceMap)

// Ensure that node2 is placed after node1
layoutData.sequenceConstraints.placeAfter(node1, node2)
// Also place another node at the very start
layoutData.sequenceConstraints.placeAtHead(firstNodeInLayer)