const arr = []
      for (let i = 0; i < 10000; i++) {
        const tempStr = Math.random().toString(36).substr(2, 6)
        arr.push(tempStr)
      }
      //es6提供的new Set也可以去重
      let items = new Set(arr)
      const result = Array.from(items)
      console.log(result)
      console.log('去重后的个数：' + result.length)