--- # Logger [Winston](https://github.com/winstonjs/winston)-based logger allowing to create nested namespaces. It provides: * Nested namespaces * Each namespace includes its "path" in the logs generated by it (the path is formed by its label appended to all its parent labels). * Coloured logs, with format: `HH:mm:ss:SS [level][...parentLabel:parentLabel:label?] message` * Store logs from each different namespace in a different array. * Store logs from all namespaces in a global store. * Each namespace log level can be set separately, and child namespaces can inherit the change or not. * Emit events whenever a log is added to any store. ## Usage A brief example: ```js const { Logger } = require("@mocks-server/logger"); // Create root logger const logger = new Logger(); logger.setLevel("debug"); logger.info("Hello world"); // 18:41:43:16 [info] Hello world const dbLogger = logger.namespace("db"); dbLogger.verbose("Hello from database component"); // 18:41:43:16 [verbose][db] Hello from database component const dbConnectionLogger = dbLogger.namespace("connection"); dbConnectionLogger.debug("Connecting"); // 18:41:43:16 [debug][db:connection] Connecting console.log(dbConnectionLogger.store); /* [ '18:41:43:16 [debug][db:connection] Connecting' ] */ console.log(logger.globalStore); /* [ '18:41:43:16 [info] Hello world', '18:41:43:16 [verbose][db] Hello from database component', '18:41:43:16 [debug][db:connection] Connecting' ] */ ``` ## API ### Logger constructor ```js const logger = new Logger(); ``` * __`Logger(label?, options?)`__. Returns a `logger` instance. * __`label`__ _(String)_: Label for the root namespace. Optional. * __`options`__ _(Object)_: Optional. * __`level`__ _(String)_: - Initial level, can be one of `silent`, `error`, `warn`, `info`, `verbose`, `debug` or `silly`. * __`storeLimit`__ _(Number)_: - Limit of logs to store in the root namespace `store` array. The option will be inherited by all children namespaces. Default is 1000. * __`globalStoreLimit`__ _(Number)_: - Limit of logs to store in the global `store` array, which stores logs from all nested namespaces. Default is 1000. ### logger instance * __`error(message)`__: The message will be logged always except if the current `level` is `silent`. * __`warn(message)`__: The message will be logged always except if the current `level` is `error` or `silent`. * __`info(message`__: The message will be logged whenever the current `level` is not `error`, `warn` or `silent`. * __`verbose(message)`__: The message will be logged whenever the current `level` is upper or equal than `verbose`. * __`debug(message)`__: The message will be logged whenever the current `level` is upper or equal than `debug`. * __`silly(message)`__: The message will be logged whenever the current `level` is upper or equal than `silly`. * __`setLevel(level, [options])`__: Sets the logger current log level for the current namespace and all children namespaces recursively. * `level` _(String)_: Level can be one of `silent`, `error`, `warn`, `info`, `verbose`, `debug` or `silly`. * `options` _(Object)_: * `transport` _(String)_: The `Winston` transport in which the level has to be set. Can be one of `console` or `store`. If not provided, the level is set to all transports. In the root logger, changes in the `store` transport will be applied also to the `globalStore` transport. * `propagate` _(Boolean)_: Propagates the level change to all children namespaces recursively or not. Default is `true`. * `pinned` _(Boolean)_: When `true`, next level changes coming from propagations will be ignored and the transport/transports will keep the defined `level`. Default is `false`. * `forcePropagation` _(Boolean)_: When `true`, the propagation will ignore `pinned` levels and will always override them. * __`namespace(label)`__: Creates and returns a new child namespace or returns an already existent one when the `label` already exists. The returned namespace has the same `Logger` methods described here. The created namespace will inherit the current namespace level. * `label` _(String)_: Label for the new namespace. It will be displayed as part of the log `[label]`, appended to parent namespaces labels. * __`cleanStore()`__ Empties the namespace store array. * __`onChangeStore(callback)`__: Allows to add a listener that will be executed whenever a log is added to the current namespace store. __It returns a function that removes the listener once executed__. * `callback()` _(Function)_: Callback to be executed. * __`onChangeGlobalStore(callback)`__: Allows to add a listener that will be executed whenever a log is added to the global store. __It returns a function that removes the listener once executed__. * `callback()` _(Function)_: Callback to be executed. * __`store`__: Returns an array with logs stored in the current namespace. * __`globalStore`__: Returns an array with logs stored in all namespaces, including those from the ancestors. There is only one global namespace for each `Logger` instance, no matter the amount of namespaces it has. * __`label`__: Getter returning the namespace label. * __`level`__: Getter returning the current namespace level. * __`root`__: Getter returning the root namespace instance.