using ensureIndex in mongodb schema using mongoose

Question

I would like to call ensureIndex on the authorName, what is the command and where in this code should I put it?

var mongoose = require(         


        

Answer 1

you can call Schema#index method to create index

let urlSchema = new Schema({
    url: String,
    status: Number
  }
);
urlSchema.index({ url: 1 }, { unique: true, background: true, dropDups: true });

you can listen createing index event.

let UrlModel = mongoose.model('url', urlSchema);
UrlModel.on('index', function(error) {
  if (error && error.message) {
    console.log(`Url collection create index error:${error.message}`);
  }
});

Note: the process of creating index is asynchronous.so when you create unique index,you cannot insert duplicate data. or creating index will fail;