Debugging

For development purposes it might come handy to enable logging and debug mode:

return MikroORM.init({
  debug: true,
});

By doing this MikroORM will start using console.log() function to dump all queries:

[query] select `e0`.* from `author` as `e0` where `e0`.`name` = ? limit ? [took 2 ms]
[query] begin [took 1 ms]
[query] insert into `author` (`name`, `email`, `created_at`, `updated_at`, `terms_accepted`) values (?, ?, ?, ?, ?) [took 2 ms]
[query] commit [took 2 ms]

It is also useful for debugging problems with entity discovery, as you will see information about every processed entity:

[discovery] ORM entity discovery started
[discovery] - processing entity Author
[discovery] - using cached metadata for entity Author
[discovery] - processing entity Book
[discovery] - processing entity BookTag
[discovery] - entity discovery finished after 13 ms

Custom Logger

You can also provide your own logger via logger option.

return MikroORM.init({
  debug: true,
  logger: msg => myCustomLogger.log(msg),
});

Logger Namespaces

There are multiple Logger Namespaces that you can specifically request, while omitting the rest. Just specify array of them via the debug option:

return MikroORM.init({
  debug: ['query'], // now only queries will be logged
});

Currently there are 4 namespaces – query, query-params, discovery and info.

If you provide query-params then you must also provide query in order for it to take effect.