arraybuffer類型數據轉為json

let content = file.data;//arraybuffer類型數據
let resBlob = new Blob([content])
let reader = new FileReader()
reader.readAsText(resBlob, "utf-8")
reader.onload = () => {
  let res = JSON.parse(reader.result)
  console.log(JSON.parse(reader.result))
}