collection.ensureindex mongoose code example

Example 1: (node:3168) DeprecationWarning: collection.ensureIndex is deprecated. Use createIndexes instead. (Use `node --trace-deprecation ...` to show where the warning was created)

mongoose.set('useCreateIndex', true);

Example 2: deprecationwarning: mongoose

mongoose.connect("mongodb://localhost/test1", { useNewUrlParser: true, useUnifiedTopology: true });
//test1 is databse name