API: StylePresets

Presets

Name	numFormat	Other styles	Use for
header	—	Bold, size 12, 1F4E79 fill, white text, centered	Headers (when applied manually)
currency	#,##0.00	Right-aligned	Amounts
percent	0.00%	Right-aligned	Ratios, growth rates
date	yyyy-MM-dd	Centered	Date columns
datetime	yyyy-MM-dd HH:mm	Centered	Date-time columns
dataRow	—	Left-aligned, vertically centered, thin BFBFBF bottom border	Data rows
bordered	—	Thin BFBFBF box on all four sides	Table-wide borders
danger	—	Bold red C00000, centered	Risk / anomalies

Full definitions

The presets are plain constant objects — the exact values shipped in src/style-presets.ts:

export const StylePresets = {
  header: {
    font: { bold: true, size: 12, color: "FFFFFF" },
    fill: { pattern: "solid", fgColor: "1F4E79" },
    alignment: { horizontal: "center", vertical: "center" },
  },
  currency: { numFormat: "#,##0.00", alignment: { horizontal: "right" } },
  percent: { numFormat: "0.00%", alignment: { horizontal: "right" } },
  date: { numFormat: "yyyy-MM-dd", alignment: { horizontal: "center" } },
  datetime: {
    numFormat: "yyyy-MM-dd HH:mm",
    alignment: { horizontal: "center" },
  },
  dataRow: {
    alignment: { horizontal: "left", vertical: "center" },
    border: { bottom: { style: "thin", color: "BFBFBF" } },
  },
  bordered: {
    border: {
      top: { style: "thin", color: "BFBFBF" },
      bottom: { style: "thin", color: "BFBFBF" },
      left: { style: "thin", color: "BFBFBF" },
      right: { style: "thin", color: "BFBFBF" },
    },
  },
  danger: {
    font: { color: "C00000", bold: true },
    alignment: { horizontal: "center" },
  },
} as const;

Usage

import { exportExcel, StylePresets } from "@marcusok/excel-exporter";

columns: [
  { prop: "amount", label: "Amount", width: 14, style: StylePresets.currency },
  { prop: "rate", label: "Growth", width: 12, style: StylePresets.percent },
  { prop: "date", label: "Date", width: 12, style: StylePresets.date },
  { prop: "flag", label: "Status", width: 10, style: StylePresets.danger },
];

Where to attach a style

Target	Field	Merge semantics
One column's data cells	ColumnConfig.style	deep-merges over sheet dataStyle
One column's header (group headers included)	ColumnConfig.headerStyle	replaces sheet headerStyle wholesale
Every data cell (base layer)	SheetConfig.dataStyle	overridable field by field by column style
Every header cell (default)	SheetConfig.headerStyle	replaced wholesale by column headerStyle
The injected index column	IndexColumnOptions.style / .headerStyle	same rules as a regular column

Deriving variants

Presets are not factories and not frozen — derive variants with object spread:

// Amounts without decimals
style: { ...StylePresets.currency, numFormat: "#,##0" }

// Only change one nested field: spread the nested object too,
// otherwise its siblings are lost (spread is a shallow merge)
style: { ...StylePresets.header, font: { ...StylePresets.header.font, size: 14 } }

The spread is your merge, done before the library sees the config — distinct from the engine's field-level deep merge between dataStyle and a column's style. Ready-made recipes (report template, header overrides, numFormat tweaks): see the Styling guide.

Type

import type { StylePresetName } from "@marcusok/excel-exporter";

const name: StylePresetName = "currency"; // "header" | "currency" | "percent" | "date" | "datetime" | "dataRow" | "bordered" | "danger"

StylePresetName parameterizes preset selection:

const columnPresets: Record<string, StylePresetName> = {
  amount: "currency",
  rate: "percent",
  orderDate: "date",
};

const columns = Object.entries(columnPresets).map(([prop, name]) => ({
  prop,
  label: prop,
  style: StylePresets[name],
}));

Column style applies to data cells, not headers. For header styling use the headerStyle field directly (sheet-level SheetConfig.headerStyle sets the default; column-level ColumnConfig.headerStyle overrides it), e.g. headerStyle: StylePresets.header.