本来好好运行一年多的云函数 ，最近突然总是报错，本地调试又是正常的

// 得到具体图书查询结果

    const books = await db.collection('Books')

    .where({typeCode: "JG"})

    .orderBy('creatTime', 'desc')

    .skip((pageNum - 1) * pageSize)

    .limit(pageSize).get()

报错信息：

{ Error: errCode: -1 unknown error | errMsg: collection.get:fail SyntaxError: Unexpected token c in JSON at position 17; at collection.get api;

at returnAsCloudSDKError (/var/user/node_modules/wx-server-sdk/index.js:6027:16)

at Object.returnAsFinalCloudSDKError (/var/user/node_modules/wx-server-sdk/index.js:6041:15)

at Promise (/var/user/node_modules/wx-server-sdk/index.js:1432:32)

at <anonymous>

at process._tickCallback (internal/process/next_tick.js:188:7)

errCode: -1,

errMsg: 'collection.get:fail SyntaxError: Unexpected token c in JSON at position 17; at collection.get api; ' }