xlsxStyles

xl/styles.xml part — indexed registries (numFmts/fonts/fills/borders/cellXfs/dxfs) §18.8.

Module xlsxStyles | Source packages/front/office/ooxml/src/xlsx/styles.js | Deps ooxmlErrors, xml, ooxmlShared | Worker-safe yes

Cells point into cellXfs through their s attribute. Six indexed tables: numFmts (format codes), fonts, fills, borders, cellStyleXfs (templates) and cellXfs (concrete formats), plus dxfs (differential formats) for conditional formatting.

Resolve

const styles = runtime.resolve('xlsxStyles');
// Returns: { parse, serialize, bytesOf, defaults, withCellXfs, withDxfs,
//            parseFont, renderFont, parseFill, renderFill,
//            parseBorder, renderBorder,
//            parseXf, renderXf, parseDxf, renderDxf,
//            parseColor, renderColor,
//            REL_TYPE_STYLES, CT_STYLES }

API

The two helpers are not symmetric: withCellXfs ignores any object you already have and starts from defaults(), whereas withDxfs takes the target object as its first argument and mutates it.

Model (summary)

{
    numFmts: [{ id, formatCode }],
    fonts: [{ size?, color?, name?, family?, scheme?, bold?, italic?, underline?, strike? }],
    fills: [{ patternType, fgColor?, bgColor? }],
    borders: [{ left?, right?, top?, bottom?, diagonal?, diagonalUp?, diagonalDown? }],
    cellStyleXfs: [xf],
    cellXfs: [xf],
    cellStyles: [{ name, xfId, builtinId? }],
    dxfs?: [dxf],
    _extras?
}

xf := { numFmtId?, fontId?, fillId?, borderId?, xfId?,
        applyFont?, applyFill?, applyBorder?, applyNumberFormat?, applyAlignment?,
        alignment?: { horizontal?, vertical?, wrapText?, indent?,
                      textRotation?, shrinkToFit? } }

borderSide := { style?, color? }   // 'thin'|'medium'|'thick'|…
color := { rgb?: 'AARRGGBB', theme?: number, tint?: number, indexed?: number }

defaults() returns one Calibri 11 font, the two mandatory fills (none + gray125), one empty border, one cellStyleXfs / cellXfs entry and the Normal cell style.

Examples

Allocate a bold red format

const styles = runtime.resolve('xlsxStyles');

// `withCellXfs` starts from defaults() — build the object it returns,
// then extend it.
const { styles: obj, indices } = styles.withCellXfs([
    { fontId: 1, applyFont: true }
]);
obj.fonts.push({ size: 11, name: 'Calibri', bold: true, color: { rgb: 'FFCC0000' } });
const sIndex = indices[0];    // set `s: sIndex` on the relevant cells

Custom number format

obj.numFmts.push({ id: 164, formatCode: '0.00%;[Red]-0.00%' });
obj.cellXfs.push({ numFmtId: 164, applyNumberFormat: true, xfId: 0 });

Differential formats for conditional formatting

const dxfIndices = styles.withDxfs(obj, [
    { fill: { patternType: 'solid', bgColor: { rgb: 'FFFFC7CE' } } }
]);
// dxfIndices[0] is the `dxfId` a conditional-formatting rule references.

Notes

• numFmt ids 0–163 are reserved (built-ins). User-defined ones start at 164.
• color.rgb is AARRGGBB (alpha first); prefix FF for fully opaque.
• xf.xfId references cellStyleXfs (the parent template); cellXfs[*].xfId is usually 0 (Normal).
• The applyFont / applyFill flags are required for Excel to honour the overrides; without them the style inherits from its parent xfId.
• Attach the object as workbook.styles before calling xlsx.write(workbook).
• A root other than <styleSheet> raises ParseError('xlsx/styles-bad-root').

See also

• xlsx — cell.s points here.
• xlsx-conditional-formatting — references dxfs.