Emitter 2a: the corpus runner, the canonical serializer and the CommonMark subset

src/adf-document.ts

@@ -0,0 +1,64 @@
+import { isJsonValue, type JsonValue } from './canonical-json.ts'
+
+export type AdfAttributes = { [key: string]: JsonValue }
+
+export type AdfMark = {
+  attrs?: AdfAttributes
+  type: string
+}
+
+export type AdfNode = {
+  attrs?: AdfAttributes
+  content?: AdfNode[]
+  marks?: AdfMark[]
+  text?: string
+  type: string
+}
+
+export type AdfDocument = {
+  content?: AdfNode[]
+  type: 'doc'
+  version: number
+}
+
+const documentKeys = ['content', 'type', 'version']
+const markKeys = ['attrs', 'type']
+const nodeKeys = ['attrs', 'content', 'marks', 'text', 'type']
+
+export function isAdfDocument(value: unknown): value is AdfDocument {
+  if (!isRecord(value) || !holdsOnly(value, documentKeys)) return false
+  if (value['type'] !== 'doc') return false
+  if (typeof value['version'] !== 'number' || !Number.isFinite(value['version'])) return false
+  return !('content' in value) || isArrayOf(value['content'], isAdfNode)
+}
+
+function isAdfMark(value: unknown): value is AdfMark {
+  if (!isRecord(value) || !holdsOnly(value, markKeys)) return false
+  if (typeof value['type'] !== 'string') return false
+  return !('attrs' in value) || isAttributes(value['attrs'])
+}
+
+function isAdfNode(value: unknown): value is AdfNode {
+  if (!isRecord(value) || !holdsOnly(value, nodeKeys)) return false
+  if (typeof value['type'] !== 'string') return false
+  if ('attrs' in value && !isAttributes(value['attrs'])) return false
+  if ('content' in value && !isArrayOf(value['content'], isAdfNode)) return false
+  if ('marks' in value && !isArrayOf(value['marks'], isAdfMark)) return false
+  return !('text' in value) || typeof value['text'] === 'string'
+}
+
+function isArrayOf<T>(value: unknown, guard: (item: unknown) => item is T): value is T[] {
+  return Array.isArray(value) && value.every(guard)
+}
+
+function isAttributes(value: unknown): value is AdfAttributes {
+  return isRecord(value) && isJsonValue(value)
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null && !Array.isArray(value)
+}
+
+function holdsOnly(value: Record<string, unknown>, keys: readonly string[]): boolean {
+  return Object.keys(value).every((key) => keys.includes(key))
+}