Elegant Error Handling Code Samples

process-row-06.js

function processRow(headerFields, row) {
    const fieldsEither   = right(row).map(splitFields);
    const rowObj         = fieldsEither.chain(zipRow(headerFields));
    const rowObjWithDate = rowObj.chain(addDateStr);
    return either(showError, rowToMessage, rowObjWithDate);
}