Excel

The Excel provider exports data using exceljs.

Provider arguments

This provider is selected when type is excel.

Required fields

Field	Type	Required	Notes
type	'excel'	✅ Yes	Must be excel.
data	Array<object>	✅ Yes	Array of rows (objects).

options (optional)

Field	Type	Required	Default	Notes
options.headers	string[]	❌ No	—	If provided, defines column order/keys. If omitted, keys are derived from the first row object.
options.headersMap	Record<string,string>	❌ No	—	Maps field keys to column header titles.
options.sheetName	string	❌ No	Sheet1	Worksheet name.
options.columnOptions	Record<string, { width?: number; style?: { numFmt?: string } }>	❌ No	—	Column-level options keyed by field name (width and number format).

Example

export.service.ts

import { Injectable } from '@nestjs/common';
import { DataExporterService } from 'nestjs-export-module';

@Injectable()
export class ExportService {
  constructor(private readonly exporter: DataExporterService) {}

  async exportExcel(rows: Array<object>) {
    return this.exporter.exportAsync({
      type: 'excel',
      data: rows,
      options: {
        sheetName: 'Users',
        headers: ['id', 'name', 'salary'],
        headersMap: { id: 'ID', name: 'Name', salary: 'Salary' },
        columnOptions: {
          salary: { width: 16, style: { numFmt: '#,##0.00' } },
        },
      },
    });
  }
}

Notes

• Suitable for richer spreadsheets (multiple sheets, formatting, etc.).
• This provider returns { mimeType: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', extension: 'xlsx', data: Buffer }.