In mongoose how do I require a String field to not be null or undefined (permitting 0-length string)?

Question

I have tried this, which allows null, undefined, and complete omission of the key to be saved:

{
  myField: {
    type: String,
    validate: value => typeof value === 'string',
  },
}

and this, which does not allow '' (the empty string) to be saved:

{
  myField: {
    type: String,
    required: true,
  },
}

How do I enforce that a field is a String and present and neither null nor undefined in Mongoose without disallowing the empty string?

user_8148505 · Answer

Just write this once, and it will be applied to all schemas

mongoose.Schema.Types.String.checkRequired(v => typeof v === 'string');

See this method in official mongoose documentation & github issue

user_979647 · Answer

You can now use the 'match' property on a String. The match property takes a regex. So you could use something like this:

myfield: {type: String, required: true, match: /^(?!\s*$).+/}