const regex = /(\$\r?\n)|\r?\n/g;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(\\$\\r?\\n)|\\r?\\n', 'g')
const str = `1598356988 228938 90 18 \$\$\$
1598356994 228548 90 1031 \$\$\$
1598357029 229550 90 751 \$\$\$
1598357031 228916 89 586 Частичное подтверждение:
2020-08-20 02:24 = 4л.;
2020-08-19 02:46 = 4л.;
\$\$\$
1598357036 229337 90 5 \$\$\$
1598357079 229054 90 586 \$\$\$
1598357092 228547 90 1031 \$\$\$
1598357092 229053 90 586 \$\$\$
`;
const subst = `$1`;
// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);
console.log('Substitution result: ', result);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions