how to query like record 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: equivalente like en mongodb

db.tu_coleccion.find({"campo": /.*busqueda.*/});