mongoDB - Text Search in multiple fields using node.js - node.js

Question

I am trying to using Node.JS connected to a MongoDB database (all hosted on heroku, so using MongoLab plugin) to perform a text search. I would like to search certain fields (strings or arrays of strings, however I can change them to all strings need be) of my documents for a variable keyword.
What the code below hopefully would do is search either the 'title' field or 'ingredients' field for the keyword variable, and then return those results.
I am dubious of the ensureIndex lines (tried both ensureIndex and createIndex) because removing them does not change the functionality of the program.
Any help would be appreciated!
app.get('/searchtitle', function(request, response) {
response.header("Access-Control-Allow-Origin", "*");
response.header("Access-Control-Allow-Headers", "X-Requested-With");
response.set('Content-Type', 'application/json');
var type = request.query.type;
var keyword = request.query.keyword;
if (type == 'title') {
db.collection('Test_Recipes').ensureIndex( { title: "text" } );
db.collection('Test_Recipes').find({
$text: {$search: keyword }
}).toArray(function(err, results){
response.send(JSON.stringify(results)) });
}
else {
console.log("in else case: type is "
+ type + " and keyword is " +keyword);
db.collection('Test_Recipes').ensureIndex({ingredients :"text"});
db.collection('Test_Recipes').find({
ingredients: {$elemMatch: keyword } })
.toArray(function(err, results){
response.send(JSON.stringify(results)) });
}
}

Answer 1

Indexes, as in any databases, need to be created only once, when the collection is first created. Index creation is a costly operation and a blocking operation.
As of mongoDB 3.0 there is no difference between the methods createIndex() and ensureIndex(), and either of them should be used to create indexes on the collection, only once, in the server side, when the collection is created and be modified only when required.
To index both the title and the ingredients fields, you need to create index on the collection as:
db.collection.createIndex({"ingredients":"text","title":"text"})
This would ensure that both the fields are indexed, when the document is inserted.
I am dubious of the ensureIndex lines (tried both ensureIndex and
createIndex) because removing them does not change the functionality
of the program. Any help would be appreciated!
This is because, how the createIndex() operation behaves. Only the first call to this method succeeds and others are simply ignored, if the indexes are created on the same field(s) again.
Then just querying, as below would query for the keyword in both the title and ingredients fields.
var type = request.query.type;
var keyword = request.query.keyword;
db.collection('Test_Recipes').find({
$text: {$search: keyword }
}).toArray(function(err, results){
response.send(JSON.stringify(results))
});