Bulk Load from JSON

When you have an array of objects — from a fetch call, a JSON file, or a database query — populate the grid in one pass and rebuild the formula graph only once.

Full example

import { createReogrid } from '@reogrid/lite';

const data = [
  { product: 'Widget',    price:  9.99, qty: 40 },
  { product: 'Gadget',    price: 24.50, qty: 12 },
  { product: 'Gizmo',     price: 39.00, qty:  7 },
  // ...hundreds more
];

const { worksheet } = createReogrid('#grid');

const columns: { key: keyof typeof data[0]; label: string; format?: string }[] = [
  { key: 'product', label: 'Product' },
  { key: 'price',   label: 'Price',    format: '$#,##0.00' },
  { key: 'qty',     label: 'Quantity' },
];

// 1. Write the header
columns.forEach((col, c) => {
  worksheet.cell(0, c).setValue(col.label).setStyle({ bold: true, backgroundColor: '#f1f5f9' });
});

// 2. Write all data rows — no intermediate re-renders
data.forEach((row, r) => {
  columns.forEach((col, c) => {
    worksheet.cell(r + 1, c).setValue(String(row[col.key]));
  });
});

// 3. Apply column formats once
columns.forEach((col, c) => {
  if (col.format) {
    worksheet.range(1, c, data.length, c).setFormat(col.format);
  }
});

// 4. Rebuild the formula graph once at the end (only if you wrote any formulas above)
worksheet.rebuildFormulas();

Why rebuildFormulas() at the end?

Each setCellInput with a formula re-evaluates dependents immediately. When you’re loading 10,000 cells, that’s 10,000 graph walks. Calling rebuildFormulas() once after all writes is an order of magnitude faster for large bulk loads.

If your data has no formulas, you can skip step 4 entirely.

Performance tips

• Avoid per-cell setStyle in a hot loop. Apply styles to ranges or columns: worksheet.range('A1:C1').setStyle({ bold: true }).
• Size columns up front, not per-cell: worksheet.column(0).width = 200.
• Set rows.setCount() to preallocate the row count if you know it:

  worksheet.rows.setCount(data.length + 1);

Lite tier limit

Lite caps at 100 rows × 26 columns. Writes beyond those limits are dropped with a console.warn. For larger datasets, use @reogrid/pro.

See also

• Cell Data
• Row & Column