一些场景，比如canvas获取的图片，或者微信开发sdk返回的图片格式是data:img格式的，我们需要上传到服务器上，那就需要进行转化。
1、将dataURL转成Blob

// base64 转 blob
dataURItoBlob(dataURI) {// convert base64/URLEncoded data component to raw binary data held in a stringlet byteString;if (dataURI.split(',')[0].indexOf('base64') >= 0) {byteString = atob(dataURI.split(',')[1]);} else byteString = unescape(dataURI.split(',')[1]);// separate out the mime componentconst mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];// write the bytes of the string to a typed arrayconst ia = new Uint8Array(byteString.length);for (let i = 0; i < byteString.length; i++) {ia[i] = byteString.charCodeAt(i);}return new Blob([ia], { type: mimeString });
},

2、构建Form上传表单

const blob = dataURItoBlob(imgDataUrl);
const formData = new FormData();
// formData.append('auth', state.token.auth); 可以选择性的加入一些鉴权
formData.append('file', blob);

3、进行数据上传，我这里使用的是axios

 const params = {url: '/store/file',payload: formData};const data = await this.upload(params);

我已经对axios进行了封装

export const upload = (params) => {const { url, payload } = paramsreturn axios.post(url, payload, {headers: {'Content-Type': 'multipart/form-data'}}).then(x => x.data)
}