Mongodb Full text search, get the matched string in the document

I am trying to implement FTS feature with node and mongdodb backend. In the search result, I would also like to project a new field, i.e the matched string in the document. This would give it a google like feel. Has anyone got ideas on this without having write lots of own custom functions?

The schema looks like this

var version = new mongoose.Schema({     
    name:   String,     
    owner: String, 
    reviewer: String,
    date_of_modification: Date,
    comments:           String,             
    hints: [String],
    global:   Boolean,      
    **content:  { type: [String], index: true }**
    version_no: Number,                 
});


var artifactSchema= new mongoose.Schema({

    pid :   String,
    trashed :  Boolean,
    baseline : Number,
    versions : [version],                   
});

I would like to create an index on the content field of Version model.

I know its a little late but recently I did it with MEAN+angucomplete AngularJS Query e.g. http://localhost:8080/api/search?s= Express Query

router.route('/search')
    .get(function(req, res) {
        Dept.aggregate(
                { $match : { 'Product.name' : new RegExp(query, 'gi') } },
                { $project : { name : 1, _id : 1,  'Product.name' : 1, 'Product._id' : 1} },
                { $unwind : "$Product" },
                { $group : {
                    _id : "$_id",
                    Category : { $addToSet : "$name"},
                    Product : { $push : "$Product"}
                }}
        )
    });

Angucomplete Markup

    <div angucomplete-alt id="depts"
                     placeholder="Click Here to Search across Whole Store"
                     pause="300" 
                     selected-object="selectedDepts" 
                     remote-url="http://localhost:8080/api/search?s="
                     remote-url-data-field="Departments"
                     remote-url-response-formatter="responseFormatted"     
                     search-fields="name"
                     title-field="name"
                     minlength="1"
                     maxlength="20"
                     description-field="description"
                     override-suggestions="true" 
                     match-class="highlight"
                     autocapitalize="on" autocorrect="off" autocomplete="off" 
                     input-class="form-control form-control-small"
                     class="col-lg-8"
                     ng-pattern="/^[A-Za-z]+$/"
                     docs-search-input-focus
                     >
   </div>