Odoo web provides a helper for easy and clear questioning of models query() which functions as a shortcut for the usual combination of search() and read(). As shown in example code given below.

model.query(['name', 'login', 'user_email', 'signature'])
     .filter([['active', '=', true], ['company_id', '=', main_company]])
     .limit(15)
     .all().then(function (users) {
    // do work with users records
});
model.call('search', [['active', '=', true], ['company_id', '=', main_company]], {limit: 15})
    .then(function (ids) {
        return model.call('read', [ids, ['name', 'login', 'user_email', 'signature']]);
    })
    .then(function (users) {
        // do work with users records
    });

Note- Query() represents the query being built. It is immutable, methods to customize the query actually return a modified copy, so it's possible to use the original and the new version side-by-side. See Query() for its customization options.