I am trying to have a field in the schema based on another.
I found this solution:
const PostSchema = new Schema({
title: { type: String, required: true },
titleUpperCase: { type: String }
content: { type: String, required: true },
creation: { type: Date, default: Date.now() }
})
PostSchema.pre('save', (next) => {
this.titleUpperCase = this.title.toUpperCase()
next()
})
In the above code, I want the value of the titleUpperCase field to be based on the title field
but the problem is i give an error says: TypeError: Cannot read properties of undefined (reading 'title')
CodePudding user response:
Because you are using an arrow function, the "this" keyword is not what you want it to be. Basically, whenever you are using mongoose hooks like a pre save hook in this case, you should always use a normal function for a callback.
PostSchema.pre('save', function(next) {
this.titleUpperCase = this.title.toUpperCase()
next()
})
I believe this should work.