又拍云FORM API结合axios上传示例，对着官方小程序库稍微改了下就能用：https://github.com/upyun/wechat-sdk

upyun.js

/**
 * const upyun = new Upyun({
 *   bucket: "test-bucket",
 *   operator: "admin-user",
 *   getSignatureUrl: "https://example.com/upyun/getSignature"
 * });
 *
 * upyun.upload({
 *   file: file,
 *   remotePath: '/dev/{year}/{mon}/{day}/{filename}{.suffix}',
 *     success: function(res) {
 *       console.log(res);
 *     },
 *     fail: function(err) {
 *       console.log(err);
 *     },
 * })
 *
 */
function Upyun (options) {
    this.bucket = options.bucket
    this.operator = options.operator
    this.getSignatureUrl = options.getSignatureUrl
}

Upyun.prototype.upload = function (options) {
    var self = this
    if (!options.remotePath) {
        options.remotePath = options.localPath.split('//')[1]
    }
    var date = (new Date()).toGMTString()
    var opts = {
        'save-key': options.remotePath,
        bucket: self.bucket,
        expiration: Math.round(new Date().getTime() / 1000) + 3600,
        date: date
    }
    var policy = Base64.encode(JSON.stringify(opts))
    var data = [ 'POST', '/' + self.bucket, date, policy ].join('&')
    self.getSignature(data, function (err, signature) {
        if (err) {
            options.fail && options.fail(err)
            options.complete && options.complete(err)
            return
        }
        var formData = new FormData();
        formData.append("file", options.file);
        formData.append("authorization", `UPYUN ${self.operator}:${signature}`);
        formData.append("policy", policy);
        axios({
            method: "post",
            url: `https://v0.api.upyun.com/${self.bucket}`,
            data: formData,
            headers: { "Content-Type": "multipart/form-data" }
        }).then(function (res) {
            options.success(res.data);
        }).catch(function (err) {
            options.fail(err);
        })
    })
}

Upyun.prototype.getSignature = function (data, cb) {
    axios({
        url: this.getSignatureUrl,
        method: "get",
        params: { data: data }
    }).then(function (res) {
        cb(null, res.data.signature);
    }).catch(function (err) {
        cb(err);
    })
}

/* eslint-disable */
var Base64 = {
    // private property
    _keyStr: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=',
    // public method for encoding
    encode: function (input) {
        var output = ''
        var chr1, chr2, chr3, enc1, enc2, enc3, enc4
        var i = 0
        input = Base64._utf8_encode(input)
        while (i < input.length) {
            chr1 = input.charCodeAt(i++)
            chr2 = input.charCodeAt(i++)
            chr3 = input.charCodeAt(i++)
            enc1 = chr1 >> 2
            enc2 = ((chr1 & 3) << 4) | (chr2 >> 4)
            enc3 = ((chr2 & 15) << 2) | (chr3 >> 6)
            enc4 = chr3 & 63
            if (isNaN(chr2)) {
                enc3 = enc4 = 64
            } else if (isNaN(chr3)) {
                enc4 = 64
            }
            output = output +
                this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
                this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4)
        }
        return output
    },
    // public method for decoding
    decode: function (input) {
        var output = ''
        var chr1, chr2, chr3
        var enc1, enc2, enc3, enc4
        var i = 0
        input = input.replace(/[^A-Za-z0-9\+\/\=]/g, '')
        while (i < input.length) {
            enc1 = this._keyStr.indexOf(input.charAt(i++))
            enc2 = this._keyStr.indexOf(input.charAt(i++))
            enc3 = this._keyStr.indexOf(input.charAt(i++))
            enc4 = this._keyStr.indexOf(input.charAt(i++))
            chr1 = (enc1 << 2) | (enc2 >> 4)
            chr2 = ((enc2 & 15) << 4) | (enc3 >> 2)
            chr3 = ((enc3 & 3) << 6) | enc4
            output = output + String.fromCharCode(chr1)
            if (enc3 != 64) {
                output = output + String.fromCharCode(chr2)
            }
            if (enc4 != 64) {
                output = output + String.fromCharCode(chr3)
            }
        }
        output = Base64._utf8_decode(output)
        return output
    },
    // private method for UTF-8 encoding
    _utf8_encode: function (string) {
        string = string.replace(/\r\n/g, '\n')
        var utftext = ''
        for (var n = 0; n < string.length; n++) {
            var c = string.charCodeAt(n)
            if (c < 128) {
                utftext += String.fromCharCode(c)
            } else if ((c > 127) && (c < 2048)) {
                utftext += String.fromCharCode((c >> 6) | 192)
                utftext += String.fromCharCode((c & 63) | 128)
            } else {
                utftext += String.fromCharCode((c >> 12) | 224)
                utftext += String.fromCharCode(((c >> 6) & 63) | 128)
                utftext += String.fromCharCode((c & 63) | 128)
            }
        }
        return utftext
    },
    // private method for UTF-8 decoding
    _utf8_decode: function (utftext) {
        var string = ''
        var i = 0
        var c = c1 = c2 = 0
        while (i < utftext.length) {
            c = utftext.charCodeAt(i)
            if (c < 128) {
                string += String.fromCharCode(c)
                i++
            } else if ((c > 191) && (c < 224)) {
                c2 = utftext.charCodeAt(i + 1)
                string += String.fromCharCode(((c & 31) << 6) | (c2 & 63))
                i += 2
            } else {
                c2 = utftext.charCodeAt(i + 1)
                c3 = utftext.charCodeAt(i + 2)
                string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63))
                i += 3
            }
        }
        return string
    }
}