Merge pull request #120 from conorbronsdon/fix/export-editor-defaults

Treat the editor's default textAlign: null as lossless in draft export

Author: conorbronsdon

docs/export.md

@@ -41,7 +41,8 @@ API body remains null; a malformed JSON body remains its original string.
 | `unavailable` | Markdown could not be produced; the original source and a diagnostic remain available |
 
 `unsupported_nodes` entries name a JSON-pointer-style path, node/mark type and
-reason. Unknown widgets and embeds get explicit Markdown placeholders. Their
+reason. The editor stores `textAlign: null` (default alignment) on paragraphs and
+headings; that value is lossless and not reported, while any other alignment is. Unknown widgets and embeds get explicit Markdown placeholders. Their
 content stays in the original body rather than being presented as a complete
 flattened export. Unsupported marks retain their text and report omitted
 formatting. Native image dimensions/layout attributes are reported; alt text,

src/__tests__/draft-export.test.ts

@@ -127,6 +127,35 @@ describe("loss-aware reverse Markdown conversion", () => {
     expect(reverse([{ type: "paywall" }, { type: "paywall" }]).unsupported_nodes).toContainEqual(expect.objectContaining({ type: "paywall" }));
     expect(reverse([{ type: "ordered_list", attrs: { order: 1_000_000_000 }, content: [{ type: "list_item", content: [paragraph(text("A"))] }] }]).status).toBe("partial");
   });
+  it("treats the editor's default textAlign: null as lossless and still reports real alignment", () => {
+    const aligned = (align: unknown) => ({ attrs: { textAlign: align } });
+    const editorDoc = [
+      { type: "heading", attrs: { level: 2, textAlign: null }, content: [text("Title")] },
+      { ...paragraph(text("Body "), text("bold", [{ type: "bold" }])), ...aligned(null) },
+      { type: "blockquote", content: [{ ...paragraph(text("Quoted")), ...aligned(null) }] },
+    ];
+    const result = reverse(editorDoc);
+    expect(result.status).toBe("converted");
+    expect(result.unsupported_nodes).toEqual([]);
+    expect(result.markdown).toBe("## Title\n\nBody **bold**\n\n> Quoted\n");
+    for (const align of ["center", "right", ""]) {
+      const partial = reverse([{ ...paragraph(text("x")), ...aligned(align) }]);
+      expect(partial.status).toBe("partial");
+      expect(partial.unsupported_nodes).toContainEqual(expect.objectContaining({ path: "/content/0/attrs", type: "paragraph" }));
+    }
+    expect(reverse([{ type: "heading", attrs: { level: 2, textAlign: "center" }, content: [text("T")] }]).status).toBe("partial");
+    expect(reverse([{ ...paragraph(text("x")), attrs: { textAlign: null, indent: 1 } }]).status).toBe("partial");
+  });
+
+  it("exports a body captured from the editor, with textAlign: null, as converted", () => {
+    const fixture = JSON.parse(readFileSync(new URL("./fixtures/footnotes-editor.json", import.meta.url), "utf8"));
+    const withEditorDefaults = JSON.parse(JSON.stringify(fixture.document), (key, value) =>
+      value && typeof value === "object" && value.type === "paragraph" ? { ...value, attrs: { textAlign: null } } : value);
+    const result = prosemirrorToMarkdown(JSON.stringify(withEditorDefaults));
+    expect(result.status).toBe("converted");
+    expect(convertMarkdown(result.markdown!).document).toEqual(fixture.document);
+  });
+
   it("exports editor footnotes and reimports the identical structure", () => {
     const fixture = JSON.parse(readFileSync(new URL("./fixtures/footnotes-editor.json", import.meta.url), "utf8"));
     const result = prosemirrorToMarkdown(JSON.stringify(fixture.document));

src/utils/prosemirror-to-markdown.ts

@@ -22,6 +22,8 @@ const kind = (n: Node) => Object.hasOwn(aliases, n.type) ? aliases[n.type] : n.t
 const children = (n: Node): unknown[] => Array.isArray(n.content) ? n.content : [];
 const attrs = (n: Node): Record<string, unknown> => object(n.attrs) ? n.attrs : {};
 const literal = (value: string): PhrasingContent => ({ type: "text", value });
+// The editor stores textAlign: null (default alignment) on paragraphs and headings; only that value maps losslessly.
+const defaultAlignment = (a: Record<string, unknown>): string[] => Object.hasOwn(a, "textAlign") && a.textAlign === null ? ["textAlign"] : [];
 const safeUrl = (value: unknown, image = false): value is string => {
   if (typeof value !== "string" || /[\u0000-\u0020\u007f]/.test(value)) return false;
   try {
@@ -175,11 +177,11 @@ export function prosemirrorToMarkdown(source: string): MarkdownExport {
     if (Array.isArray(value.marks) && value.marks.length) report(at + "/marks", value.type, "Block marks are retained only in source_prosemirror.");
     switch (type) {
       case "paragraph":
-        check(value, at);
+        check(value, at, defaultAlignment(a));
         if (!content.length) report(at, type, "An empty paragraph has no distinct Markdown representation.");
         return [{ type: "paragraph", children: inline(content, at + "/content") }];
       case "heading":
-        check(value, at, ["level"]);
+        check(value, at, ["level", ...defaultAlignment(a)]);
         if (![1, 2, 3, 4, 5, 6].includes(Number(a.level)) || typeof a.level !== "number") return placeholder(at, type, "Invalid heading level retained in original source.");
         return [{ type: "heading", depth: a.level as 1 | 2 | 3 | 4 | 5 | 6, children: inline(content, at + "/content") }];
       case "blockquote":