Function unify

packages/effect/src/SchemaAST.ts:1613–1695

(candidates: ReadonlyArray<AST>)

/** @internal */
export const unify = (candidates: ReadonlyArray<AST>): Array<AST> => {
  const cs = sortCandidates(candidates)
  const out: Array<AST> = []
  const uniques: { [K in AST["_tag"] | "{}"]?: AST } = {}
  const literals: Array<LiteralValue | symbol> = []
  for (const ast of cs) {
    switch (ast._tag) {
      case "NeverKeyword":
        break
      case "AnyKeyword":
        return [anyKeyword]
      case "UnknownKeyword":
        return [unknownKeyword]
      // uniques
      case "ObjectKeyword":
      case "UndefinedKeyword":
      case "VoidKeyword":
      case "StringKeyword":
      case "NumberKeyword":
      case "BooleanKeyword":
      case "BigIntKeyword":
      case "SymbolKeyword": {
        if (!uniques[ast._tag]) {
          uniques[ast._tag] = ast
          out.push(ast)
        }
        break
      }
      case "Literal": {
        const type = typeof ast.literal
        switch (type) {
          case "string":
          case "number":
          case "bigint":
          case "boolean": {
            const _tag = literalMap[type]
            if (!uniques[_tag] && !literals.includes(ast.literal)) {
              literals.push(ast.literal)
              out.push(ast)
            }
            break
          }
          // null
          case "object": {
            if (!literals.includes(ast.literal)) {
              literals.push(ast.literal)
              out.push(ast)
            }
            break
          }
        }
        break
      }
      case "UniqueSymbol": {
        if (!uniques["SymbolKeyword"] && !literals.includes(ast.symbol)) {
          literals.push(ast.symbol)
          out.push(ast)
        }