node：你还在用readFile和writeFile？fs新方式快速读写文件，支持大文件读写，安全放心才是首选

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文件操作

• 优点：快速读写，支持大文件读写，支持自动关闭close

• 啥也不说，先上代码吧，自己封装的：

  const fs = require('fs')
  const path = require('path')
  
  class FileUtils {
      constructor() {
  
      }
  
      checkFile(path) {
          return new Promise((resolve, reject) => {
              try {
                  let result = fs.existsSync(path);
                  if (result) {
                      resolve(true)
                  } else {
                      resolve(false)
                  }
              } catch (e) {
                  reject(e)
              }
          });
      }
  
      readFile(path, opts = 'utf8') {
          return new Promise((resolve, reject) => {
              try {
                  var input = fs.createReadStream(path, {
                      encoding: 'utf8',
                      autoClose: true,
                  });
  
                  var remaining = '';
  
                  input.on('data', function (data) {
                      remaining += data;
                      var index = remaining.indexOf('\n');
                      var last = 0;
                      while (index > -1) {
                          var line = remaining.substring(last, index);
                          last = index + 1;
                          func(line);
                          index = remaining.indexOf('\n', last);
                      }
  
                      remaining = remaining.substring(last);
                  });
  
                  input.on('end', function () {
                      resolve(remaining)
                  });
              } catch (e) {
                  console.error('Error writeObjectToJsonString:', e);
                  resolve(e)
              }
  
          })
      }
  
      writeFile(path, data, opts = 'utf8') {
          return new Promise((resolve, reject) => {
              var out = undefined;
                   out = fs.createWriteStream(path, {
                      encoding: 'utf8'
                  });
                  out.write(data,(error) => {
                      if (error) {
                          reject(error)
                      } else {
                          resolve()
                      }
                  });
                  out.end();
  
          })
      }
  
      mkdirs(dirname) {
          return new Promise((resolve, reject) => {
              if (!fs.existsSync(dirname)) {
                  fs.mkdir(dirname, {recursive: true}, (err) => {
                      if (err) {
                          reject(err)
                      } else {
                          resolve()
                      }
                  });
              } else {
                  resolve();
              }
  
          });
  
      }
  }
  
  module.exports = new FileUtils();