Create LaTeX booktabs-like tables in Google Docs

booktabs.gs

// Create a table with less bloat in Google Docs
// No vertical lines, and no horizontal lines except for header and footer
// Inspired by https://ctan.org/pkg/booktabs

function createBooktabsTable() {
  // Table configuration
  const numRows = 5; // Adjust as needed
  const numCols = 4; // Adjust as needed
  const doc = DocumentApp.getActiveDocument();
  createBooktabsTableInternal(numRows, numCols, doc)
}

// Apply Booktabs-style formatting
function createBooktabsTableInternal(numRows, numCols, doc) {
  const body = doc.getBody();

  // Insert a table
  const table = body.appendTable();

  // Populate the table with rows and cells
  for (let i = 0; i < numRows; i++) {
    const row = table.appendTableRow();
    for (let j = 0; j < numCols; j++) {
      const content = i === 0 ? `Header ${j + 1}` : `Row ${i}, Col ${j + 1}`
      const cell = row.appendTableCell(content);
      // Style header row
      // TODO this can be an updateTableStyle with tableRange https://googleapis.dev/nodejs/googleapis/latest/docs/interfaces/Schema$UpdateTableCellStyleRequest.html#tableStartLocation
      // but I haven’t checked how to set TextStyle inside a table cell, yet
      cell.getChild(0).asText().setBold(i === 0 ? true : false);
    }
  }
 
  doc.saveAndClose();

  // Google Apps Script alone has no means to change cell properties like borders.
  // That’s why we use Docs service. If you use this inside an Apps Script ensure to under: "Services +" add "Docs"
  const docId = doc.getId();
  const i     = body.getChildIndex(table);
  const index = Docs.Documents.get(docId).body.content[i + 1].startIndex;
  
  const noBorder    = { dashStyle: "SOLID", width: { magnitude: 0,   unit: "PT" }, color: { color: {} } };
  const thinBorder  = { dashStyle: "SOLID", width: { magnitude: 1,   unit: "PT" }, color: { color: {} } };
  const thickBorder = { dashStyle: "SOLID", width: { magnitude: 1.5, unit: "PT" }, color: { color: {} } };

  const noBorders = {
    updateTableCellStyle: {
      tableCellStyle: {
        borderRight: noBorder,
        borderLeft: noBorder,
        borderTop: noBorder,
        borderBottom: noBorder,
      },
      tableStartLocation: { index },
      fields: "borderRight,borderLeft,borderTop,borderBottom",
    }
  }

  const tableHeader = {
    updateTableCellStyle: {
      tableCellStyle: {
        borderTop: thickBorder,
        borderBottom: thinBorder,
      },
      tableRange: {
        tableCellLocation: {
          columnIndex: 0,
          rowIndex: 0,
          tableStartLocation: { index }
        },
        columnSpan: numCols, // optional ?
        rowSpan: 1, // optional ?
      },
      fields: "borderTop,borderBottom",
    }
  }


  const tableFooter = {
    updateTableCellStyle: {
      tableCellStyle: {
        borderBottom: thickBorder
      },
      tableRange: {
        tableCellLocation: {
          columnIndex: 0,
          rowIndex: numRows-1,
          tableStartLocation: { index }
        },
        columnSpan: numCols, // optional ?
        rowSpan: 1, // optional ?
      },
      fields: "borderBottom",
    }
  }

  const requests = [noBorders, tableHeader, tableFooter];
  const resp = Docs.Documents.batchUpdate({ requests }, docId);
}