read a csv file, concatenated the first two columns with a dash, and then compare to a different csv file, removing any rows from it that start with the concatenated value. only standard modules in javascript

index.tsx
// Import papaparse library (https://www.papaparse.com/)
import Papa from 'papaparse';

// URL of first CSV file
const url1 = 'https://example.com/csv1.csv';

// URL of second CSV file
const url2 = 'https://example.com/csv2.csv';

// Read first CSV file and parse it
fetch(url1)
  .then(response => response.text())
  .then(csv1 => {
    const data1 = Papa.parse(csv1, { header: true }).data;
    
    // Concatenate first two columns with a dash
    const newdata1 = data1.map(row => [row.column1, row.column2].join('-'));

    // Read second CSV file and parse it
    fetch(url2)
      .then(response => response.text())
      .then(csv2 => {
        const data2 = Papa.parse(csv2, { header: true }).data;

        // Filter out rows that start with concatenated value
        const filteredData2 = data2.filter(row => {
          const value = [row.column1, row.column2].join('-');
          return !newdata1.includes(value);
        });

        // Convert filtered rows back to CSV format
        const csv = Papa.unparse(filteredData2, { header: true });
        console.log(csv);
      });
  });
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