fix(formatter): expand large structured prop defaults

packages/syntax/src/formatter.ts

@@ -767,6 +767,28 @@ function expandStructuredStateDeclarations(lines, unit) {
   });
 }
 
+function formatStructuredPropDeclaration(value, unit, depth, printWidth) {
+  const match = /^([A-Za-z_$][\w$]*\??\s*(?::\s*[^=]+?)?\s*=\s*)([\[{][\s\S]*)$/.exec(
+    value,
+  );
+  if (!match) return null;
+
+  try {
+    const parsed = JSON.parse(match[2].trim());
+    const compact = JSON.stringify(parsed);
+    const indentation = unit.repeat(depth);
+    if (indentation.length + match[1].length + compact.length <= printWidth) return null;
+
+    const jsonLines = JSON.stringify(parsed, null, unit).split("\n");
+    return [
+      `${indentation}${match[1]}${jsonLines[0]}`,
+      ...jsonLines.slice(1).map((jsonLine) => `${indentation}${jsonLine}`),
+    ];
+  } catch {
+    return null;
+  }
+}
+
 function formatWrnPass(source: string, options: FormatWrnOptions = {}): string {
   const unit = options.insertSpaces === false ? "\t" : " ".repeat(options.tabSize ?? 4);
 
@@ -844,6 +866,18 @@ function formatWrnPass(source: string, options: FormatWrnOptions = {}): string {
       continue;
     }
 
+    const structuredProp = formatStructuredPropDeclaration(
+      value,
+      unit,
+      codeDepth + htmlDepth + controlDepth,
+      printWidth,
+    );
+    if (structuredProp) {
+      output.push(...structuredProp);
+      index += 1;
+      continue;
+    }
+
     const leadingClosingBraces = countLeadingClosingBraces(value);
 
     const closesControlBlock = isControlBlockClose(value);