Function collectUnionMembers

javascript/selenium-webdriver/generate_bidi.mjs:451–496

* Walk the `CommandData` or `EventData` union type hierarchy and collect all * leaf definition names (the actual command/event group names). * * The CDDL AST represents union groups with Properties that can be: * - An array of choice objects (each with a Type.Value pointing to the next level)

(rootName, defMap, visited = new Set())

 * A leaf is a definition that itself has a `method` property (string literal).
 */
function collectUnionMembers(rootName, defMap, visited = new Set()) {
  if (visited.has(rootName)) return new Set()
  visited.add(rootName)

  const def = defMap.get(rootName)
  if (!def) return new Set()

  const members = new Set()

  // Flatten Properties — each element is either a choice-array or a property object.
  const rawProps = def.Properties ?? []
  const allChoices = []
  for (const prop of rawProps) {
    if (Array.isArray(prop)) {
      allChoices.push(...prop)
    } else {
      allChoices.push(prop)
    }
  }

  for (const choice of allChoices) {
    // choice.Type can be a single object or an array of type alternatives.
    const typeEntries = Array.isArray(choice.Type) ? choice.Type : [choice.Type]

    for (const entry of typeEntries) {
      if (entry?.Type !== 'group' || !entry.Value) continue
      const childName = entry.Value
      const childDef = defMap.get(childName)
      if (!childDef) continue

      // A leaf has a `method` property — it is the actual command or event definition.
      const childProps = childDef.Properties ?? []
      const flat = childProps.flatMap((p) => (Array.isArray(p) ? p : [p]))
      if (flat.some((p) => p.Name === 'method')) {
        members.add(childName)
      } else {
        // Intermediate union — recurse.
        for (const m of collectUnionMembers(childName, defMap, visited)) {
          members.add(m)
        }
      }
    }
  }

  return members
}

/**
 * Build a name → definition map from the AST (deduplicated — first wins).