{"errorCode":1,"errorMessage":"user code exception caught","stackTrace":"Error: errCode: -502001 database request fail | errMsg: Update Fail: write errors: [{The dollar ($) prefixed field '$push' in 'cusers.$push' is not valid for storage.}]; \n at new CloudSDKError (/var/user/node_modules/wx-server-sdk/index.js:2503:28)\n at Object.returnAsCloudSDKError (/var/user/node_modules/wx-server-sdk/index.js:2555:16)\n at Object.checkError (/var/user/node_modules/wx-server-sdk/index.js:1260:23)\n at Query.\u003canonymous\u003e (/var/user/node_modules/wx-server-sdk/index.js:1358:41)\n at step (/var/user/node_modules/tslib/tslib.js:133:27)\n at Object.next (/var/user/node_modules/tslib/tslib.js:114:57)\n at fulfilled (/var/user/node_modules/tslib/tslib.js:104:62)\n at \u003canonymous\u003e\n at process._tickCallback (internal/process/next_tick.js:188:7)"}