@sap-ux/logger

This is a simple logging library. It uses Winston underneath to do the heavy-lifting. The API is agnostic to any particular logging library. Don't depend on any Winston-specific implemenation as the underlying library may change in the future.

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Add the package @sap-ux/logger to your project using your preferred package manager.

In Typescript/ES6, import the logger and instantiate it. By default the log level is info and the logs are sent to the console.

``typescript
import { ToolsLogger } from '@sap-ux/logger';
...

const logger = new ToolsLogger();
...
logger.info('This is an information message');
...
logger.warn('This is a warning');
...
logger.error('This is an error!');
// Can also log objects
logger.debug({a: 42, b: 'some value'});
`

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| Option | Default Value | Description |
| ------ | ------------- | ----------- |
| logLevel | LogLevel.Info | Log only if equal to or more severe than this level (supported levels) |
| transports | ConsoleTransport | An array of transports |

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Log levels are exposed an as enumeration.
The following levels are available, in decreasing order of severity:
* Error
* Warn
* Info
* Verbose
* Debug
* Silly

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These are the targets of the log messages. You can have multiple targets for a single logger. The targets can be added and removed dynamically, if required.

The following transports are currently supported:
#### ConsoleTransport
This is used to write to the console.
#### FileTransport
This is used to write to files. Logs are appended to files. Currently there's no support to rotate logs.

#### VSCodeTransport
This is used to write to an output channel in VS Code.
#### NullTransport
This is the equivalent of writing to /dev/null. If an API needs a logger and you really don't want to capture logs, you can use NullTransport to use completely ignore the logs.

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#### Logging methods
error(), warn(), info() and debug() methods can be used to either print log a string or an object.

#### Transport management
You can add(), remove() transport dynamically. transports() returns a list of the current transports of the logger.

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The unit test file can be used as an example to explore the logger's API: ./test/unit/wiston-logger/logger.test.ts

Please refer to the debugging section in the project root README for help debugging the test.

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The following options are not supported yet. There are no definite plans to add them in the future. They will be considered on a need-basis.

* Custom formatters
- VSCodeTransport logs timestamped lines
- FileTransport logs in JSON
- ConsoleTransport` logs colored and timestamped lines (piping will remove color encoding though)
* File rotation - the file transport appends to an existing file or creates a new one if missing