使用node.js更改文件 [英] change a file using node.js

问题描述

我有一个如下所示的文本文件：

I have a text file that looks like this:

./4F6cFLnAAFc.png
./4Flj9plmKGQ.png
./4fQeHtSdw80.png
./4I9iibPLdBw.png
./4J-dRA3MGc8.png
./4mdEsouIXGM.png
./4-_-wQc3EGE.png
./595Tiga1gIg.png
./60u_ctp6UIw.png
./64bH_27Ehoc.png
./64_ZfIemRGM.png
./66pQLO--Ghk.png
./69rDtSpshAw.png
./69-YUSazuic.png

I我想使用node.js用'myString'替换每行开头的。。所以每个人最终看起来像： myString / 4F6cFLnAAFc.png

I'd like to replace the . at the beginning of each line with 'myString' using node.js. So each will end up looking like: myString/4F6cFLnAAFc.png

我正在尝试使用正则表达式但是我怀疑它可以使用读写流来完成。

I am trying to use a regular expression but I suspect it can be done using read and write streams.

var fs = require('fs');

fs.readFile('filelist.txt', 'utf-8', function(err, data){
    if (err) throw err;

    console.log(typeof(data)); // string

    data.replace(/\.\/+/, 'myString');

});

什么样的正则表达式可以使用节点编辑这个文件的最佳方法是什么？

What regex will work or what's the best way to edit this file using node?

推荐答案

根据您的需要，以下是同步或异步的两个选项。

Here are two options for Sync or Async depending on what you want.

var fs = require('fs');

function readWriteAsync() {
  fs.readFile('filelist.txt', 'utf-8', function(err, data){
    if (err) throw err;

    var newValue = data.replace(/^\./gim, 'myString');

    fs.writeFile('filelistAsync.txt', newValue, 'utf-8', function (err) {
      if (err) throw err;
      console.log('filelistAsync complete');
    });
  });
}

function readWriteSync() {
  var data = fs.readFileSync('filelist.txt', 'utf-8');

  var newValue = data.replace(/^\./gim, 'myString');

  fs.writeFileSync('filelistSync.txt', newValue, 'utf-8');

  console.log('readFileSync complete');
}

readWriteAsync();
readWriteSync();

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