@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.

Quick Usage

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.

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'});

Logger Options

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

Log Levels

Log levels are exposed an as enumeration. The following levels are available, in decreasing order of severity:

• Error
• Warn
• Info
• Verbose
• Debug
• Silly

Transports

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.

Logger API

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.

Examples

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.

Not supported

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