Programmatically build dynamic query with Mongoose

Question

I\'m trying to build a search from input received from a form.

router.get(\'/data\', function(req, res) {
    var firstName=req.body.firstName,
    lastName         


        

Answer 1

For people using newer JavaScript (and especially on Node.js 7.6.0+ or Babel).

The best way I found for programmatically building queries (based on if clauses etc.) is using the Query and the alternative syntax.

let query = PersonModel().find();

if (isMale) {
    query.where('sex', 'male'); 
} else {
    query.where('sex', 'female');
}

query.where('alive', true);

// and then to run the query
const result = await query.exec();

Note the async/await usage here. It's working perfectly on Node.js 7.6.0+. If you don't want to use async/await you can just use Promises like so:

query.exec().then(result => {
    // result has your... results
});

Answer 2

To avoid checking each parameter independently you can loop through them.

var query = {};
for(var key in req.body){ //could also be req.query and req.params
  req.body[key] !== "" ? query[key] = req.body[key] : null;
}

mongoose.model('customers').find(query, function(err, customers){

})

Answer 3

try creating query object, like:

//generate query object based on availability of value 
var query = {};
if( your_variable !== "" ) {
    query["some_key"] = your_variable;
}
if( your_second_variable !== "" ) {
    query["some_other_key"] = your_second_variable;
}
mongoose.model('customers').find(query, function(err, c) {
    //do something
});