Deep copy inherited style (exceljs#1850)

* Deep copy style when a row is inserted with inherited style (exceljs#1813)

* Add tests for row's style

* Move setIfExists

* Fix equal function

lib/doc/worksheet.js

@@ -9,6 +9,7 @@ const Image = require('./image');
 const Table = require('./table');
 const DataValidations = require('./data-validations');
 const Encryptor = require('../utils/encryptor');
+const {copyStyle} = require('../utils/copy-style');
 
 // Worksheet requirements
 //  Operate as sheet inside workbook or standalone
@@ -406,10 +407,10 @@ class Worksheet {
   _copyStyle(src, dest, styleEmpty = false) {
     const rSrc = this.getRow(src);
     const rDst = this.getRow(dest);
-    rDst.style = Object.freeze({...rSrc.style});
+    rDst.style = copyStyle(rSrc.style);
     // eslint-disable-next-line no-loop-func
     rSrc.eachCell({includeEmpty: styleEmpty}, (cell, colNumber) => {
-      rDst.getCell(colNumber).style = Object.freeze({...cell.style});
+      rDst.getCell(colNumber).style = copyStyle(cell.style);
     });
     rDst.height = rSrc.height;
   }

lib/utils/copy-style.js

@@ -0,0 +1,43 @@
+const oneDepthCopy = (obj, nestKeys) => ({
+  ...obj,
+  ...nestKeys.reduce((memo, key) => {
+    if (obj[key]) memo[key] = {...obj[key]};
+    return memo;
+  }, {}),
+});
+
+const setIfExists = (src, dst, key, nestKeys = []) => {
+  if (src[key]) dst[key] = oneDepthCopy(src[key], nestKeys);
+};
+
+const isEmptyObj = obj => Object.keys(obj).length === 0;
+
+const copyStyle = style => {
+  if (!style) return style;
+  if (isEmptyObj(style)) return {};
+
+  const copied = {...style};
+
+  setIfExists(style, copied, 'font', ['color']);
+  setIfExists(style, copied, 'alignment');
+  setIfExists(style, copied, 'protection');
+  if (style.border) {
+    setIfExists(style, copied, 'border');
+    setIfExists(style.border, copied.border, 'top', ['color']);
+    setIfExists(style.border, copied.border, 'left', ['color']);
+    setIfExists(style.border, copied.border, 'bottom', ['color']);
+    setIfExists(style.border, copied.border, 'right', ['color']);
+    setIfExists(style.border, copied.border, 'diagonal', ['color']);
+  }
+
+  if (style.fill) {
+    setIfExists(style, copied, 'fill', ['fgColor', 'bgColor', 'center']);
+    if (style.fill.stops) {
+      copied.fill.stops = style.fill.stops.map(s => oneDepthCopy(s, ['color']));
+    }
+  }
+
+  return copied;
+};
+
+exports.copyStyle = copyStyle;

spec/integration/worksheet.spec.js

@@ -598,6 +598,38 @@ describe('Worksheet', () => {
       }
     });
 
+    it('should style of the inserted row with inherited style be mutable', () => {
+      const wb = new ExcelJS.Workbook();
+      const ws = wb.addWorksheet('blort');
+
+      const dateValue1 = new Date(1970, 1, 1);
+      const dateValue2 = new Date(1965, 1, 7);
+
+      ws.addRow([1, 'John Doe', dateValue1]);
+      ws.getRow(1).font = testutils.styles.fonts.comicSansUdB16;
+
+      ws.insertRow(2, [3, 'Jane Doe', dateValue2], 'i');
+      ws.insertRow(2, [2, 'Jane Doe', dateValue2], 'o');
+
+      ws.getRow(2).font = testutils.styles.fonts.broadwayRedOutline20;
+      ws.getRow(3).font = testutils.styles.fonts.broadwayRedOutline20;
+      ws.getCell('A2').font = testutils.styles.fonts.arialBlackUI14;
+      ws.getCell('A3').font = testutils.styles.fonts.arialBlackUI14;
+
+      expect(ws.getRow(2).font).not.deep.equal(
+        testutils.styles.fonts.comicSansUdB16
+      );
+      expect(ws.getRow(3).font).not.deep.equal(
+        testutils.styles.fonts.comicSansUdB16
+      );
+      expect(ws.getCell('A2').font).not.deep.equal(
+        testutils.styles.fonts.comicSansUdB16
+      );
+      expect(ws.getCell('A3').font).not.deep.equal(
+        testutils.styles.fonts.comicSansUdB16
+      );
+    });
+
     it('iterates over rows', () => {
       const wb = new ExcelJS.Workbook();
       const ws = wb.addWorksheet('blort');

spec/unit/utils/copy-style.spec.js

@@ -0,0 +1,39 @@
+const testUtils = require('../../utils/index');
+
+const {copyStyle} = verquire('utils/copy-style');
+
+const style1 = {
+  numFmt: testUtils.styles.numFmts.numFmt1,
+  font: testUtils.styles.fonts.broadwayRedOutline20,
+  alignment: testUtils.styles.namedAlignments.topLeft,
+  border: testUtils.styles.borders.thickRainbow,
+  fill: testUtils.styles.fills.redGreenDarkTrellis,
+};
+const style2 = {
+  fill: testUtils.styles.fills.rgbPathGrad,
+};
+
+describe('copyStyle', () => {
+  it('should copy a style deeply', () => {
+    const copied = copyStyle(style1);
+    expect(copied).to.deep.equal(style1);
+    expect(copied.font).to.not.equal(style1.font);
+    expect(copied.alignment).to.not.equal(style1.alignment);
+    expect(copied.border).to.not.equal(style1.border);
+    expect(copied.fill).to.not.equal(style1.fill);
+
+    expect(copyStyle({})).to.deep.equal({});
+  });
+
+  it('should copy fill.stops deeply', () => {
+    const copied = copyStyle(style2);
+    expect(copied.fill.stops).to.deep.equal(style2.fill.stops);
+    expect(copied.fill.stops).to.not.equal(style2.fill.stops);
+    expect(copied.fill.stops[0]).to.not.equal(style2.fill.stops[0]);
+  });
+
+  it('should return the argument if a falsy value passed', () => {
+    expect(copyStyle(null)).to.equal(null);
+    expect(copyStyle(undefined)).to.equal(undefined);
+  });
+});