Depriciation Warning

[KanikaBakshi]

DeprecationWarning: collection.ensureIndex is deprecated. Use createIndexes instead.

[asimimamabdullah]

I have getting the same issue

[BhaskarPaul]

add mongoose.set("useCreateIndex", true)

[hichamabboud]

When you connect your mongoose.connect() add useCreateIndex : true,
so your code should look like this.

mongoose.connect('mongodb URL goes here' , {
useCreateIndex : true,
useFindAndModify:true,
useNewUrlParser :true,
useUnifiedTopology : true
})