wx.base64ToArrayBuffer(base64)返回为空？

根据https://mp.weixin.qq.com/debug/wxadoc/dev/api/api-util.html的例子。

const arrayBuffer = new Uint8Array([11, 22, 33])const base64 = wx.arrayBufferToBase64(arrayBuffer)

转换为

CxYh

然后倒过来

const base64 = 'CxYh'const arrayBuffer = wx.base64ToArrayBuffer(base64)

arrayBuffer为空？