utils_csvDownload.mjs

/**
## mapp.utils.csvDownload()

@module /utils/csvDownload
*/

export default function csvDownload(data, params = {}) {
  if (!Array.isArray(data)) {
    console.warn('Array argument for csvDownload must be an array');
    return;
  }

  // Set comma as default separator.
  params.separator ??= ',';

  const rows = data.map((record) => {
    const row = Array.isArray(params.fields)
      ? fieldsFunction(record, params.fields)
      : Object.values(record);

    return row.join(params.separator);
  });

  // Set default type for the blob.
  params.type ??= 'text/csv;charset=utf-8;';

  params.join ??= '\r\n';

  params.title ??= 'file';

  if (params.header && Array.isArray(params.fields)) {
    // Unshift the header row with either the title or field names.
    rows.unshift(params.fields.map((field) => field.title || field.field));
  }

  const blob = new Blob([rows.join(params.join)], { type: params.type });

  const link = document.createElement('a');

  link.download = `${params.title}.csv`;
  link.href = URL.createObjectURL(blob);
  link.dataset.downloadurl = ['csv', link.download, link.href].join(':');
  link.style.display = 'none';
  document.body.append(link);
  link.click();
  link.remove();
}

function fieldsFunction(record, fields) {
  return fields.map((field) => {
    if (!field.field) return;

    // Escape quotes in string value.
    if (typeof record[field.field] === 'string' && field.string) {
      return `"${record[field.field].replaceAll('"', '""')}"`;
    }

    // Format number toLocaleString
    if (field.formatter === 'toLocaleString') {
      const val = parseFloat(record[field.field]);

      if (isNaN(val)) return;

      return `"${val.toLocaleString(field.locale || navigator.language, field.options)}"`;
    }

    return record[field.field];
  });
}