Function intersectUnionMembers

packages/effect/src/Schema.ts:3311–3444

(
  xs: ReadonlyArray<AST.AST>,
  ys: ReadonlyArray<AST.AST>,
  path: ReadonlyArray<PropertyKey>
)

const getTypes = (ast: AST.AST): ReadonlyArray<AST.AST> => AST.isUnion(ast) ? ast.types : [ast]

const intersectUnionMembers = (
  xs: ReadonlyArray<AST.AST>,
  ys: ReadonlyArray<AST.AST>,
  path: ReadonlyArray<PropertyKey>
): Array<AST.AST> =>
  array_.flatMap(xs, (x) =>
    array_.flatMap(ys, (y) => {
      switch (y._tag) {
        case "Literal": {
          if (
            (Predicate.isString(y.literal) && AST.isStringKeyword(x) ||
              (Predicate.isNumber(y.literal) && AST.isNumberKeyword(x)) ||
              (Predicate.isBoolean(y.literal) && AST.isBooleanKeyword(x)))
          ) {
            return [y]
          }
          break
        }
        case "StringKeyword": {
          if (y === AST.stringKeyword) {
            if (AST.isStringKeyword(x) || (AST.isLiteral(x) && Predicate.isString(x.literal))) {
              return [x]
            } else if (AST.isRefinement(x)) {
              return addRefinementToMembers(x, intersectUnionMembers(getTypes(x.from), [y], path))
            }
          } else if (x === AST.stringKeyword) {
            return [y]
          }
          break
        }
        case "NumberKeyword": {
          if (y === AST.numberKeyword) {
            if (AST.isNumberKeyword(x) || (AST.isLiteral(x) && Predicate.isNumber(x.literal))) {
              return [x]
            } else if (AST.isRefinement(x)) {
              return addRefinementToMembers(x, intersectUnionMembers(getTypes(x.from), [y], path))
            }
          } else if (x === AST.numberKeyword) {
            return [y]
          }
          break
        }
        case "BooleanKeyword": {
          if (y === AST.booleanKeyword) {
            if (AST.isBooleanKeyword(x) || (AST.isLiteral(x) && Predicate.isBoolean(x.literal))) {
              return [x]
            } else if (AST.isRefinement(x)) {
              return addRefinementToMembers(x, intersectUnionMembers(getTypes(x.from), [y], path))
            }
          } else if (x === AST.booleanKeyword) {
            return [y]
          }
          break
        }
        case "Union":
          return intersectUnionMembers(getTypes(x), y.types, path)
        case "Suspend":
          return [new AST.Suspend(() => extendAST(x, y.f(), path))]