refactor(label): flatten defaultFont into two top-level optional fields

Replaces the nested defaultFont: { fontId, height } object with two
independent optional fields defaultFontId and defaultFontHeight. The
nested shape forced an all-or-nothing UI: typing one field at a time
either lost the partial input (deadlock) or required a fragile merge
helper that conflated 'absent' and 'cleared' states.

Flat fields let each input persist independently; the generator emits
^CF only when both are set. Removes mergeDefaultFont; tests updated
including a new pair that asserts ^CF is omitted on partial state.

Author: u8array

src/components/Properties/PropertiesPanel.tsx

@@ -436,13 +436,9 @@ function LabelConfigPanel({
                 type="text"
                 className={inputCls}
                 maxLength={2}
-                value={label.defaultFont?.fontId ?? ""}
+                value={label.defaultFontId ?? ""}
                 onChange={(e) =>
-                  onUpdate({
-                    defaultFont: mergeDefaultFont(label.defaultFont, {
-                      fontId: e.target.value,
-                    }),
-                  })
+                  onUpdate({ defaultFontId: e.target.value || undefined })
                 }
               />
             </div>
@@ -454,12 +450,10 @@ function LabelConfigPanel({
                 type="number"
                 className={inputCls}
                 min={1}
-                value={label.defaultFont?.height ?? ""}
+                value={label.defaultFontHeight ?? ""}
                 onChange={(e) =>
                   onUpdate({
-                    defaultFont: mergeDefaultFont(label.defaultFont, {
-                      height: parseIntOrUndef(e.target.value),
-                    }),
+                    defaultFontHeight: parseIntOrUndef(e.target.value),
                   })
                 }
               />
@@ -476,16 +470,3 @@ function parseIntOrUndef(raw: string): number | undefined {
   const n = parseInt(raw, 10);
   return isNaN(n) ? undefined : n;
 }
-
-function mergeDefaultFont(
-  current: LabelConfig["defaultFont"],
-  patch: { fontId?: string; height?: number },
-): LabelConfig["defaultFont"] {
-  // `in` distinguishes "key absent from patch" (keep current value) from
-  // "key set to undefined" (user just cleared the input). `??` would conflate
-  // the two and silently keep the old value when the user clears a field.
-  const fontId = "fontId" in patch ? patch.fontId : current?.fontId;
-  const height = "height" in patch ? patch.height : current?.height;
-  if (!fontId || height === undefined) return undefined;
-  return { fontId, height };
-}

src/lib/zplGenerator.test.ts

@@ -88,14 +88,24 @@ describe('generateZPL — printer params', () => {
     expect(generateZPL(BASE_LABEL, [])).not.toContain('^PO');
   });
 
-  it('emits ^CF when defaultFont is set', () => {
+  it('emits ^CF when both defaultFontId and defaultFontHeight are set', () => {
     const zpl = generateZPL(
-      { ...BASE_LABEL, defaultFont: { fontId: '0', height: 30 } },
+      { ...BASE_LABEL, defaultFontId: '0', defaultFontHeight: 30 },
       [],
     );
     expect(zpl).toContain('^CF0,30');
   });
 
+  it('omits ^CF when defaultFontId is set without defaultFontHeight', () => {
+    expect(generateZPL({ ...BASE_LABEL, defaultFontId: '0' }, []))
+      .not.toContain('^CF');
+  });
+
+  it('omits ^CF when defaultFontHeight is set without defaultFontId', () => {
+    expect(generateZPL({ ...BASE_LABEL, defaultFontHeight: 30 }, []))
+      .not.toContain('^CF');
+  });
+
   it('emits printer params in canonical header order before ^LS', () => {
     const zpl = generateZPL(
       {
@@ -105,7 +115,8 @@ describe('generateZPL — printer params', () => {
         printSpeed: 6,
         darkness: 10,
         printOrientation: 'I',
-        defaultFont: { fontId: '0', height: 30 },
+        defaultFontId: '0',
+        defaultFontHeight: 30,
         labelShift: 5,
       },
       [],
@@ -215,14 +226,16 @@ describe('generateZPL — parse/generate roundtrip', () => {
       darkness: 0,
       mediaType: 'D',
       printOrientation: 'I',
-      defaultFont: { fontId: '0', height: 30 },
+      defaultFontId: '0',
+      defaultFontHeight: 30,
     };
     const regenerated = generateZPL(label, []);
     const { labelConfig } = parseZPL(regenerated, BASE_LABEL.dpmm);
     expect(labelConfig.printSpeed).toBe(8);
     expect(labelConfig.darkness).toBe(0);
     expect(labelConfig.mediaType).toBe('D');
     expect(labelConfig.printOrientation).toBe('I');
-    expect(labelConfig.defaultFont).toEqual({ fontId: '0', height: 30 });
+    expect(labelConfig.defaultFontId).toBe('0');
+    expect(labelConfig.defaultFontHeight).toBe(30);
   });
 });

src/lib/zplGenerator.ts

@@ -30,8 +30,8 @@ export function generateZPL(label: LabelConfig, objects: LabelObject[]): string
   // darkness=0 is a valid value (printer baseline), so check undefined explicitly.
   if (label.darkness !== undefined) lines.push(`^MD${label.darkness}`);
   if (label.printOrientation) lines.push(`^PO${label.printOrientation}`);
-  if (label.defaultFont) {
-    lines.push(`^CF${label.defaultFont.fontId},${label.defaultFont.height}`);
+  if (label.defaultFontId && label.defaultFontHeight !== undefined) {
+    lines.push(`^CF${label.defaultFontId},${label.defaultFontHeight}`);
   }
   if (label.labelShift) lines.push(`^LS${label.labelShift}`);
 

src/lib/zplParser.test.ts

@@ -546,9 +546,10 @@ describe('parseZPL — printer params', () => {
     expect(parseZPL('^XA^POI^XZ', 8).labelConfig.printOrientation).toBe('I');
   });
 
-  it('parses ^CF default font with id and height', () => {
+  it('parses ^CF into defaultFontId and defaultFontHeight', () => {
     const { labelConfig } = parseZPL('^XA^CF0,40^XZ', 8);
-    expect(labelConfig.defaultFont).toEqual({ fontId: '0', height: 40 });
+    expect(labelConfig.defaultFontId).toBe('0');
+    expect(labelConfig.defaultFontHeight).toBe(40);
   });
 });
 

src/lib/zplParser.ts

@@ -649,8 +649,9 @@ export function parseZPL(zpl: string, dpmm = 8): ParsedZPL {
       const explicitHeight = parseInt(p[1] ?? "", 10);
       cfHeight = isNaN(explicitHeight) ? cfHeight : explicitHeight;
       cfWidth = int(p[2], cfWidth);
-      if (fontId && !isNaN(explicitHeight) && explicitHeight > 0) {
-        labelConfig.defaultFont = { fontId, height: explicitHeight };
+      if (fontId) labelConfig.defaultFontId = fontId;
+      if (!isNaN(explicitHeight) && explicitHeight > 0) {
+        labelConfig.defaultFontHeight = explicitHeight;
       }
     },
 

src/types/ObjectType.ts

@@ -12,12 +12,8 @@ export const labelConfigSchema = z.object({
   darkness: z.number().int().min(-30).max(30).optional(),
   mediaType: z.enum(['T', 'D']).optional(),
   printOrientation: z.enum(['N', 'I']).optional(),
-  defaultFont: z
-    .object({
-      fontId: z.string().min(1),
-      height: z.number().int().positive(),
-    })
-    .optional(),
+  defaultFontId: z.string().min(1).optional(),
+  defaultFontHeight: z.number().int().positive().optional(),
 });
 
 export type LabelConfig = z.infer<typeof labelConfigSchema>;