Read the node tables backwards, a directive to the node and marks it names

src/markdown/block-directive-marks.ts

@@ -0,0 +1,23 @@
+import type { AdfMark } from '../adf/document.ts'
+import type { JsonValue } from '../json-value.ts'
+import { isAdfMark } from '../adf/document.ts'
+import { serializeCanonicalJson } from '../canonical-json.ts'
+
+export const marksAttribute = 'marks'
+
+export function markValues(marks: readonly AdfMark[]): JsonValue {
+  return marks.map((mark) => {
+    const attrs = mark.attrs ?? {}
+    return Object.keys(attrs).length === 0 ? { type: mark.type } : { attrs, type: mark.type }
+  })
+}
+
+export function readMarkValues(value: JsonValue): AdfMark[] | undefined {
+  if (!Array.isArray(value) || value.length === 0) return undefined
+  const marks: AdfMark[] = []
+  for (const item of value) {
+    if (!isAdfMark(item)) return undefined
+    marks.push(item)
+  }
+  return serializeCanonicalJson(markValues(marks), 'compact') === serializeCanonicalJson(value, 'compact') ? marks : undefined
+}