Node.js大文件流处理方法解析

const fs = require('fs');
<p>const readStream = fs.createReadStream('large-file.log', {
encoding: 'utf8',
highWaterMark: 64 * 1024 // 每次读取 64KB
});</p><p>readStream.on('data', (chunk) => {
// 处理每个数据块，比如搜索关键词
console.log(<code>Received chunk of ${chunk.length} characters</code>);
});</p><p>readStream.on('end', () => {
console.log('文件读取完成');
});</p><p>readStream.on('error', (err) => {
console.error('读取出错:', err);
});</p>

const fs = require('fs');
<p>const readStream = fs.createReadStream('source-big-file.zip');
const writeStream = fs.createWriteStream('copy-big-file.zip');</p><p>readStream.pipe(writeStream);</p><p>writeStream.on('finish', () => {
console.log('文件复制完成');
});</p>

const fs = require('fs');
const { Transform } = require('stream');
<p>const upperCaseTransform = new Transform({
transform(chunk, encoding, callback) {
callback(null, chunk.toString().toUpperCase());
}
});</p><p>const readStream = fs.createReadStream('input.txt');
const writeStream = fs.createWriteStream('output.txt');</p><p>readStream.pipe(upperCaseTransform).pipe(writeStream);</p>