自从发布了我最初的答案后，我发现split是一个非常容易使用的节点模块，用于文件中的行读取;它也接受可选参数。

var split = require('split');
fs.createReadStream(file)
    .pipe(split())
    .on('data', function (line) {
      //each chunk now is a seperate line! 
    });

还没有对非常大的文件进行测试。如果有，请告诉我们。

从Node.js v0.12和Node.js v4.0.0开始，有一个稳定的readline核心模块。下面是从文件中读取行，不需要任何外部模块的最简单方法:

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();

或者:

var lineReader = require('readline').createInterface({
  input: require('fs').createReadStream('file.in')
});

lineReader.on('line', function (line) {
  console.log('Line from file:', line);
});

最后一行被正确读取(截至Node v0.12或更高版本)，即使没有最后的\n。

更新:此示例已添加到Node的API官方文档中。

基于生成器的行阅读器:https://github.com/neurosnap/gen-readlines

var fs = require('fs');
var readlines = require('gen-readlines');

fs.open('./file.txt', 'r', function(err, fd) {
  if (err) throw err;
  fs.fstat(fd, function(err, stats) {
    if (err) throw err;

    for (var line of readlines(fd, stats.size)) {
      console.log(line.toString());
    }

  });
});

require('fs').readFileSync('file.txt', 'utf-8').split(/\r?\n/).forEach(function(line){
  console.log(line);
})

function createLineReader(fileName){
    var EM = require("events").EventEmitter
    var ev = new EM()
    var stream = require("fs").createReadStream(fileName)
    var remainder = null;
    stream.on("data",function(data){
        if(remainder != null){//append newly received data chunk
            var tmp = new Buffer(remainder.length+data.length)
            remainder.copy(tmp)
            data.copy(tmp,remainder.length)
            data = tmp;
        }
        var start = 0;
        for(var i=0; i<data.length; i++){
            if(data[i] == 10){ //\n new line
                var line = data.slice(start,i)
                ev.emit("line", line)
                start = i+1;
            }
        }
        if(start<data.length){
            remainder = data.slice(start);
        }else{
            remainder = null;
        }
    })

    stream.on("end",function(){
        if(null!=remainder) ev.emit("line",remainder)
    })

    return ev
}


//---------main---------------
fileName = process.argv[2]

lineReader = createLineReader(fileName)
lineReader.on("line",function(line){
    console.log(line.toString())
    //console.log("++++++++++++++++++++")
})

对于这样一个简单的操作，不应该依赖于任何第三方模块。去容易。

var fs = require('fs'),
    readline = require('readline');

var rd = readline.createInterface({
    input: fs.createReadStream('/path/to/file'),
    output: process.stdout,
    console: false
});

rd.on('line', function(line) {
    console.log(line);
});