how to query like in mongodb code example

Example 1: mongodb find like

db.users.find({"name": /.*m.*/});

db.users.find({"name": /m/});

Items.find({"description": {$regex: ".*" + variable + ".*"}}).fetch();

Example 2: like mongodb

db.collection.find( { "url": { "$regex": ".*a.*"} } );