js base64转文件流
时间: 2023-07-06 22:04:01 浏览: 53
以下是将 base64 转为文件流的 JavaScript 代码示例:
```javascript
function base64toBlob(base64Data, contentType) {
contentType = contentType || '';
var sliceSize = 1024;
var byteCharacters = atob(base64Data);
var bytesLength = byteCharacters.length;
var slicesCount = Math.ceil(bytesLength / sliceSize);
var byteArrays = new Array(slicesCount);
for (var sliceIndex = 0; sliceIndex < slicesCount; ++sliceIndex) {
var begin = sliceIndex * sliceSize;
var end = Math.min(begin + sliceSize, bytesLength);
var bytes = new Array(end - begin);
for (var offset = begin, i = 0 ; offset < end; ++i, ++offset) {
bytes[i] = byteCharacters[offset].charCodeAt(0);
}
byteArrays[sliceIndex] = new Uint8Array(bytes);
}
return new Blob(byteArrays, { type: contentType });
}
function downloadFile(base64Data, fileName, contentType) {
var blob = base64toBlob(base64Data, contentType);
var link = document.createElement('a');
link.href = window.URL.createObjectURL(blob);
link.download = fileName;
link.click();
}
```
使用示例:
```javascript
var base64Data = "data:image/jpeg;base64,/9j/4AAQSkZJRgABAQEASABIAAD...";
var fileName = "image.jpg";
var contentType = "image/jpeg";
downloadFile(base64Data, fileName, contentType);
```
其中,`base64Data` 是 base64 编码后的数据,`fileName` 是要保存的文件名,`contentType` 是文件类型。`downloadFile` 函数会将 base64 数据转化为文件流并下载到本地。