如何检查字段是否未在 EJS 中填写

问：

https://pastebin.com/GxNe01LB

错误：

Error updating welcome channel: CastError: Cast to string failed for value "[ '', '' ]" (type Array) at path "welcomeChannel" at SchemaString.cast (C:\Users\mariu\Desktop\moxx handler\node_modules\mongoose\lib\schema\string.js:606:11) at SchemaType.applySetters (C:\Users\mariu\Desktop\moxx handler\node_modules\mongoose\lib\schematype.js:1219:12) at SchemaString.castForQuery (C:\Users\mariu\Desktop\moxx handler\node_modules\mongoose\lib\schema\string.js:690:15) at castUpdateVal (C:\Users\mariu\Desktop\moxx handler\node_modules\mongoose\lib\helpers\query\castUpdate.js:576:19) at walkUpdatePath (C:\Users\mariu\Desktop\moxx handler\node_modules\mongoose\lib\helpers\query\castUpdate.js:381:24) at castUpdate (C:\Users\mariu\Desktop\moxx handler\node_modules\mongoose\lib\helpers\query\castUpdate.js:110:7) at model.Query._castUpdate (C:\Users\mariu\Desktop\moxx handler\node_modules\mongoose\lib\query.js:4709:10) at model.Query._updateThunk (C:\Users\mariu\Desktop\moxx handler\node_modules\mongoose\lib\query.js:3876:25) at model.Query._updateOne (C:\Users\mariu\Desktop\moxx handler\node_modules\mongoose\lib\query.js:3964:23) at model.Query.exec (C:\Users\mariu\Desktop\moxx handler\node_modules\mongoose\lib\query.js:4429:28) { stringValue:“[ ''， '' ]”ay' }, messageFormat: undefined, kind: 'string', value: [ '', '' ], path: 'welcomeChannel', reason: null, valueType: 'Arr

我试图检查该字段是否已归档，但我不知道如何，因为它不起作用