text: 
  const fs = require('fs')
  
  // console.time('ttt')
  // let hrt = process.hrtime()
  
  // let nowTime = new Date().getTime()
  
  // let ran = (Math.random() * 10000 + 2) >>> 0
  // let ran2 = (Math.random() * 1000 + 1) >>> 0
  // let sl = (Math.random() * 10 + 5) >>> 0
  
  // let a = (ran.toString(36) + hrt[0].toString(36) + hrt[1].toString(36) + nowTime.toString(36) + ran2.toString(36))
  
  // let s = (a + a.slice(-sl)).substring(0, 25)
  
  // console.timeEnd('ttt')
  // console.log(hrt)
  // console.log(s)
  // console.log(s.length)
  
  
  // let oldBuf = fs.readFileSync('../fastdata/b.json')
  
  // console.log('oldBuf string   ', oldBuf.length)
  
  // let isHave = oldBuf.includes(`"_fast_id":"2cofdx2c7m70kpxqev54j6xqe"`)
  // console.log('isHave>>>>><<<<<    ', isHave)
  
  
  // let start = oldBuf.indexOf(`{"_fast_id":"2cofdx2c7m70kpxqev54j6xqe"`)
  // if(start === -1){
  //   // 没有
  //   return
  // }
  // let end = oldBuf.indexOf(`,{"_fast_id"`, start + 10)
  // if(end === -1){
  //   end = oldBuf.length - 1
  // }
  
  // let result = oldBuf.slice(start, end)
  
  
  // console.log('start:   ', start)
  // console.log('end  ', end)
  
  // console.log('result:>>>   ', JSON.parse(result.toString()))
  
  
  
  
  
  
  /** find */
  
  let buf = Buffer.from(`my name is one name abc`)
  let tempB = Buffer.from('name,')
  console.log(buf.indexOf(tempB, 15))
  console.log(buf.lastIndexOf(tempB, 3))
  
  console.log(buf.slice(1, 4))
  console.log(buf.slice(1, 4).toString())