在JavaScript中搜索存储在S3中的.txt文件的关键字的最佳方式是什么？

const AWS = require('aws-sdk');
const s3 = new AWS.S3();

const bucketName = 'your-bucket-name';
const fileName = 'your-file-name.txt';
const keyword = 'your-keyword';

const params = {
  Bucket: bucketName,
  Key: fileName
};

s3.getObject(params, (err, data) => {
  if (err) {
    console.error(err);
  } else {
    const fileContent = data.Body.toString('utf-8');
    const keywordIndex = fileContent.indexOf(keyword);
    
    if (keywordIndex !== -1) {
      console.log(`Keyword "${keyword}" found at index ${keywordIndex}`);
    } else {
      console.log(`Keyword "${keyword}" not found`);
    }
  }
});