errCode: -502001,

errMsg: "document.update:fail -502001 database request fail. [FailedOperation.Update] (FailedToParse) '$pull' is empty. You must specify a field like so: {$pull: {<field>: ...}}

await transaction.collection('art_follows').doc(artId).update({

            data: {

              follows: _.pull(item => item[0] === openid && item.length > 1)

            }

          }).then(res => {

            console.log('更新成功', res);

          }).catch(err => {

            console.error('更新失败', err);

          }); 

我想删除follows字段中，其中个openid的子数组，上面函数要怎么修复。

数据集合art_follows{

  "_id": "record3",

title:xxx

  "follows": [

    ["openid1", "avlxx", "ddd"],

    ["openid2", "avlxx", "ddd"],

    ["openid3", "avlxx", "ddd"]

  ]

}