MIME类型和blob

/**
 * blobData 流文件
 * blobType 导出类型
 * fileName 导出文件名称
 * ..attr 其他信息
 */
export function dowloadBlobFile(blobData, blobType, fileName, ...attr) {
    const blob = new Blob([blobData], {
        type: blobType || "application/vnd.ms-excel",
    })
    const objectUrl = URL.createObjectURL(blob)
    const link = document.createElement("a")
    link.style.display = "none"
    link.href = objectUrl
    document.body.appendChild(link)
    link.click()
    document.body.removeChild(link)
}

// base64  to blob二进制
function dataURItoBlob(dataURI) {
    const mimeString = dataURI.split(",")[0].split(":")[1].split(";")[0] // mime类型
    const byteString = atob(dataURI.split(",")[1]) // base64 解码
    const arrayBuffer = new ArrayBuffer(byteString.length) // 创建缓冲数组
    const intArray = new Uint8Array(arrayBuffer) // 创建视图

    for (let i = 0; i < byteString.length; i++) {
        intArray[i] = byteString.charCodeAt(i)
    }
    return new Blob([intArray], { type: mimeString })
}

// blob二进制 to base64
function blobToDataURI(blob, callback) {
    const reader = new FileReader()
    reader.onload = function (e) {
        callback(e.target.result)
    }
    reader.readAsDataURL(blob)
}