老话题了，但这个很管用:

var rl = readline.createInterface({
      input : fs.createReadStream('/path/file.txt'),
      output: process.stdout,
      terminal: false
})
rl.on('line',function(line){
     console.log(line) //or parse line
})

简单。不需要外部模块。

我用这个:

function emitLines(stream, re){
    re = re && /\n/;
    var buffer = '';

    stream.on('data', stream_data);
    stream.on('end', stream_end);

    function stream_data(data){
        buffer += data;
        flush();
    }//stream_data

    function stream_end(){
        if(buffer) stream.emmit('line', buffer);
    }//stream_end


    function flush(){
        var re = /\n/;
        var match;
        while(match = re.exec(buffer)){
            var index = match.index + match[0].length;
            stream.emit('line', buffer.substring(0, index));
            buffer = buffer.substring(index);
            re.lastIndex = 0;
        }
    }//flush

}//emitLines

在流上使用此函数并侦听将发出的行事件。

gr-

2019年更新

Nodejs官方文档中已经发布了一个很棒的例子。在这里

这需要在您的机器上安装最新的Nodejs。> 11.4

const fs = require('fs');
const readline = require('readline');

async function processLineByLine() {
  const fileStream = fs.createReadStream('input.txt');

  const rl = readline.createInterface({
    input: fileStream,
    crlfDelay: Infinity
  });
  // Note: we use the crlfDelay option to recognize all instances of CR LF
  // ('\r\n') in input.txt as a single line break.

  for await (const line of rl) {
    // Each line in input.txt will be successively available here as `line`.
    console.log(`Line from file: ${line}`);
  }
}

processLineByLine();

编辑:

使用转换流。

使用BufferedReader，您可以读取行。

new BufferedReader ("lorem ipsum", { encoding: "utf8" })
    .on ("error", function (error){
        console.log ("error: " + error);
    })
    .on ("line", function (line){
        console.log ("line: " + line);
    })
    .on ("end", function (){
        console.log ("EOF");
    })
    .read ();

在Node.js v18.11.0中添加了一个逐行读取文件的新函数

filehandle.readLines([选项])

这就是如何将此功能用于想要读取的文本文件

import { open } from 'node:fs/promises';
myFileReader();
async function myFileReader() {
    const file = await open('./TextFileName.txt');
    for await (const line of file.readLines()) {
        console.log(line)
    }
}

为了了解更多read Node.js文档，这里有文件系统readlines()的链接: https://nodejs.org/api/fs.html#filehandlereadlinesoptions

我有一个小模块，它做得很好，被相当多的其他项目使用npm readline注意，在节点v10中有一个本地readline模块，所以我重新发布了我的模块linebyline https://www.npmjs.com/package/linebyline

如果你不想使用这个模块，函数很简单:

var fs = require('fs'),
EventEmitter = require('events').EventEmitter,
util = require('util'),
newlines = [
  13, // \r
  10  // \n
];
var readLine = module.exports = function(file, opts) {
if (!(this instanceof readLine)) return new readLine(file);

EventEmitter.call(this);
opts = opts || {};
var self = this,
  line = [],
  lineCount = 0,
  emit = function(line, count) {
    self.emit('line', new Buffer(line).toString(), count);
  };
  this.input = fs.createReadStream(file);
  this.input.on('open', function(fd) {
    self.emit('open', fd);
  })
  .on('data', function(data) {
   for (var i = 0; i < data.length; i++) {
    if (0 <= newlines.indexOf(data[i])) { // Newline char was found.
      lineCount++;
      if (line.length) emit(line, lineCount);
      line = []; // Empty buffer.
     } else {
      line.push(data[i]); // Buffer new line data.
     }
   }
 }).on('error', function(err) {
   self.emit('error', err);
 }).on('end', function() {
  // Emit last line if anything left over since EOF won't trigger it.
  if (line.length){
     lineCount++;
     emit(line, lineCount);
  }
  self.emit('end');
 }).on('close', function() {
   self.emit('close');
 });
};
util.inherits(readLine, EventEmitter);