Preserve QExcell border colors

src/io/excellOffice.ts

@@ -874,6 +874,7 @@ function buildStylesXml(styleRegistry = createCellStyleRegistry([])) {
   const borders = [baseBorderXml()];
   const fontIdsByKey: Record<string, number> = {};
   const fillIdsByColor: Record<string, number> = {};
+  const borderIdsByColor: Record<string, number> = {};
   const numberFormatIdsByCode: Record<string, number> = {};
   const customNumberFormats: Array<[number, string]> = [];
 
@@ -899,9 +900,11 @@ function buildStylesXml(styleRegistry = createCellStyleRegistry([])) {
 
     let borderId = 0;
     if (format.border) {
-      borderId = 1;
-      if (borders.length === 1) {
-        borders.push(formatBorderXml());
+      const borderKey = format.borderColor || "auto";
+      borderId = borderIdsByColor[borderKey] ?? borders.length;
+      if (!borderIdsByColor[borderKey]) {
+        borderIdsByColor[borderKey] = borderId;
+        borders.push(formatBorderXml(format.borderColor));
       }
     }
 
@@ -966,7 +969,7 @@ function cellFormatKey(format: CellFormat | undefined) {
     return "";
   }
 
-  return `${normalized.bold ? "1" : "0"}|${normalized.italics ? "1" : "0"}|${normalized.underline ? "1" : "0"}|${normalized.strike ? "1" : "0"}|${normalized.fontSize ?? ""}|${normalized.fontFamily ?? ""}|${normalized.textColor ?? ""}|${normalized.fillColor ?? ""}|${normalized.horizontalAlign ?? ""}|${normalized.verticalAlign ?? ""}|${normalized.wrapText ? "1" : "0"}|${normalized.border ? "1" : "0"}|${normalized.numberFormat ?? ""}`;
+  return `${normalized.bold ? "1" : "0"}|${normalized.italics ? "1" : "0"}|${normalized.underline ? "1" : "0"}|${normalized.strike ? "1" : "0"}|${normalized.fontSize ?? ""}|${normalized.fontFamily ?? ""}|${normalized.textColor ?? ""}|${normalized.fillColor ?? ""}|${normalized.horizontalAlign ?? ""}|${normalized.verticalAlign ?? ""}|${normalized.wrapText ? "1" : "0"}|${normalized.border ? "1" : "0"}|${normalized.borderColor ?? ""}|${normalized.numberFormat ?? ""}`;
 }
 
 function fontStyleKey(format: CellFormat) {
@@ -978,6 +981,7 @@ function fontStyleKey(format: CellFormat) {
 function normalizedCellFormat(format: CellFormat | undefined): CellFormat | null {
   const textColor = normalizeFillColor(format?.textColor);
   const fillColor = normalizeFillColor(format?.fillColor);
+  const borderColor = normalizeFillColor(format?.borderColor);
   const horizontalAlign = normalizedHorizontalAlign(format?.horizontalAlign);
   const verticalAlign = normalizedVerticalAlign(format?.verticalAlign);
   const numberFormat = normalizedNumberFormat(format?.numberFormat);
@@ -995,7 +999,8 @@ function normalizedCellFormat(format: CellFormat | undefined): CellFormat | null
     ...(horizontalAlign ? { horizontalAlign } : {}),
     ...(verticalAlign ? { verticalAlign } : {}),
     ...(format?.wrapText ? { wrapText: true } : {}),
-    ...(format?.border ? { border: true } : {}),
+    ...(format?.border || borderColor ? { border: true } : {}),
+    ...(borderColor ? { borderColor } : {}),
     ...(numberFormat ? { numberFormat } : {})
   };
 
@@ -1028,12 +1033,19 @@ function fillXmlToCellFormat(fill: unknown): CellFormat {
 
 function borderXmlToCellFormat(border: unknown): CellFormat {
   const record = asRecord(border);
-  const hasBorder = ["left", "right", "top", "bottom"].some((side) => {
+  const borderedSides = ["left", "right", "top", "bottom"].filter((side) => {
     const style = String(childRecord(record, side).style || childRecord(record, side)["@_style"] || "").trim().toLowerCase();
     return style && style !== "none";
   });
 
-  return hasBorder ? { border: true } : {};
+  const borderColor = borderedSides
+    .map((side) => normalizeFillColor(String(childRecord(childRecord(record, side), "color").rgb || "")))
+    .find(Boolean);
+
+  return normalizedCellFormat({
+    border: borderedSides.length > 0,
+    ...(borderColor ? { borderColor } : {})
+  }) ?? {};
 }
 
 function baseFontXml() {
@@ -1054,8 +1066,9 @@ function baseBorderXml() {
   return "<border><left/><right/><top/><bottom/><diagonal/></border>";
 }
 
-function formatBorderXml() {
-  return '<border><left style="thin"><color auto="1"/></left><right style="thin"><color auto="1"/></right><top style="thin"><color auto="1"/></top><bottom style="thin"><color auto="1"/></bottom><diagonal/></border>';
+function formatBorderXml(borderColor = "") {
+  const colorXml = borderColor ? `<color rgb="FF${borderColor}"/>` : '<color auto="1"/>';
+  return `<border><left style="thin">${colorXml}</left><right style="thin">${colorXml}</right><top style="thin">${colorXml}</top><bottom style="thin">${colorXml}</bottom><diagonal/></border>`;
 }
 
 function normalizeFillColor(value?: string) {