Are field level uniqueness constraints still supported in Mongo(ose)?

问题

It looks like mongoose supported field level uniqueness constraints in earlier versions as follows (seen in 2.7.x here):

var SomeSchema = new Schema ({
  field: {index: {unique: true}} // field level
})

I can't find any reference to it in the 4.4.x docs. Is the preferred way to do this on the schema level now, like so (seen in 4.4.x here):

SomeSchema.index({field: 1}, {unique: true}) // schema level

回答1:

Yes, unique indexes are still supported in Mongoose; see here and here in the current docs.

Examples from the linked docs:

var s = new Schema({ date: { type: Date, index: { unique: true, expires: '1d' }});
var s = new Schema({ name: { type: String, unique: true }});

Schema.path('my.path').index({ unique: true, sparse: true });
Schema.path('name').index({ unique: true });

来源：https://stackoverflow.com/questions/37035258/are-field-level-uniqueness-constraints-still-supported-in-mongoose