siyuan-note/siyuan · error

Field [notebook] should be of type [String]

Error message

Field [notebook] should be of type [String]

What it means

In /api/block/checkBlockRef, the optional notebook field must be a JSON string when present and non-null. The kernel returns this error when the value fails to unmarshal into a string (e.g. a number, boolean, or object). This check runs for all scopes, not just "notebook".

Solutions

1. Send the notebook ID as a JSON string: "notebook": "20240101120000-xyz"
2. If the ID came from a numeric source, convert with String(notebookId) before building the payload
3. Pass null or omit the field entirely when the notebook is unknown (required only when scope is "notebook")

Example fix

// before
{ "scope": "notebook", "notebook": 20240101120000, "ids": [] }
// after
{ "scope": "notebook", "notebook": "20240101120000-abcdefg", "ids": [] }

if (notebook !== null && notebook !== undefined && typeof notebook !== 'string') throw new TypeError('notebook must be a string');

const isNotebookId = (v) => typeof v === 'string' && /^\d{14}-[0-9a-z]{7}$/.test(v);

try { await fetchPost('/api/block/checkBlockRef', payload); } catch (e) { if (/Field \[notebook\] should be of type \[String\]/.test(e?.message)) { payload.notebook = String(payload.notebook); } }

When it happens

Trigger: POST /api/block/checkBlockRef with "notebook": 20240101 (numeric notebook ID), "notebook": {"id": "..."}, or "notebook": true.

Common situations: Storing notebook IDs as numbers in external scripts; passing a notebook config object instead of its ID string; template interpolation producing a non-string type.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• block [ ] type is locked: expected , got
• Field [level] should be of type [Number]
• Field [preview] should be of type [Boolean]
• Field [ ] should be of type [Array]
• Field [ ] should be of type [ ]

AI-assisted analysis of siyuan-note/siyuan@9f775e8a12 (2026-09-19). Data as JSON: /api/errors/e52df745af3665cf. Report an issue: GitHub.

Appendix: source

Thrown at kernel/apicontract/block_remaining.go:138

		request.Paths, err = readArray("paths", true, true)
		return
	case "notebook":
		// 附带块 ID 只参与租约准入，沿用仅收集字符串的规则。
		var entries []json.RawMessage
		if json.Unmarshal(fields["ids"], &entries) == nil {
			for _, entry := range entries {
				var id string
				if !bytes.Equal(entry, []byte("null")) && json.Unmarshal(entry, &id) == nil {
					request.IDs = append(request.IDs, id)
				}
			}
		}
	default:
		return request, errors.New("invalid block ref check scope")
	}
	if raw := fields["notebook"]; len(raw) != 0 && !bytes.Equal(raw, []byte("null")) {
		if json.Unmarshal(raw, &request.Notebook) != nil {
			return request, errors.New("Field [notebook] should be of type [String]")
		}
	} else if request.Scope == "notebook" {
		return request, errors.New("Field [notebook] is required")
	}
	if request.Scope == "notebook" {
		request.Notebook = strings.TrimSpace(request.Notebook)
		if request.Notebook == "" {
			return request, errors.New("Field [notebook] must not be empty")
		}
	}
	_ = json.Unmarshal(fields["id"], &request.ID)
	return
}

func decodeHeadingLevel(reader io.Reader) (request HeadingLevelRequest, err error) {
	fields, err := blockRequestFields(reader, "/api/block/getHeadingLevelTransaction")
	if err != nil {
		return request, err

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