src/types/treedoc.js
function walkDepthFirst (tree, visitor) {
  const val = walkDepthFirstRecursive(tree, visitor)
  if (val !== undefined) {
    return val
  } else {
    return visitor(null)
  }
}
function walkDepthFirst (tree, visitor) {
  const val = walkDepthFirstRecursive(tree, visitor)
  if (val !== undefined) {
    return val
  } else {
    return visitor(null)
  }
}
function walkDepthFirst ( tree , visitor ) { const val = walkDepthFirstRecursive ( tree , visitor ) if ( val !== undefined ) { return val } else { return visitor ( null ) } }
Walk the tree
Walk the tree