How do you list indexes in MongoDb?

there are few ways to list indexes...

the correct way is to do something like

db.people.getIndexes()

This returns something like this...

[
    {
        "v" : 2,
        "key" : {
            "_id" : 1
        },
        "name" : "_id_"
    },
    {
        "v" : 2,
        "key" : {
            "name" : 1.0
        },
        "name" : "name_1"
    }
]

Notice how an array is returned with each index listed as an object.

For more info, check out List Indexes | MongoDB

So the official docs claim that you can get indexes for all collections like this...

db.getCollectionNames().forEach(function(collection) {
   indexes = db[collection].getIndexes();
   print("Indexes for " + collection + ":");
   printjson(indexes);
});

Furthermore, they claim you can filter index types like this...

db.adminCommand("listDatabases").databases.forEach(function(d){
   let mdb = db.getSiblingDB(d.name);
   mdb.getCollectionInfos({ type: "collection" }).forEach(function(c){
      let currentCollection = mdb.getCollection(c.name);
      currentCollection.getIndexes().forEach(function(idx){
        let idxValues = Object.values(Object.assign({}, idx.key));

        if (idxValues.includes("hashed")) {
          print("Hashed index: " + idx.name + " on " + d.name + "." + c.name);
          printjson(idx);
        };
      });
   });
});

But REALLY these are just creative ways / scripts for using the only command for listing indexes..this is specific to a collection...

db.collection.getIndexes()

db.<collection>.getIndexes()

db.collection.getIndexes()

just check Robo3t or another DB tool and you can easily see indexes displayed via UI