Simplr Logger


Simple JavaScript logger written in TypeScript that can be used in browser or node application.

The package is most useful when used with TypeScript.

Get started

``cmd
npm install simplr-logger
`

$3

#### With default configuration

`ts
import { LoggerBuilder } from "simplr-logger";

const logger = new LoggerBuilder();
`

#### With configuration builder

`ts
import { LoggerBuilder, LoggerConfigurationBuilder, LogLevel } from "simplr-logger";
import { FileMessageHandler, ConsoleMessageHandler } from "simplr-logger/handlers";

const config = new LoggerConfigurationBuilder()
.SetDefaultLogLevel(LogLevel.Trace)
.AddWriteMessageHandlers([
{ Handler: new ConsoleMessageHandler() },
{ Handler: new FileMessageHandler("./logs.txt") }]
)
.Build();

const logger = new LoggerBuilder(config);
`

#### With simple object

`ts
import { LoggerBuilder, LogLevel, ConsoleMessageHandler } from "simplr-logger";

const logger = new LoggerBuilder({
DefaultLogLevel: {
LogLevel: LogLevel.Trace,
LogLevelIsBitMask: false
},
WriteMessageHandlers: [{
Handler: new ConsoleMessageHandler(),
LogLevel: LogLevel.Critical | LogLevel.Debug,
LogLevelIsBitMask: true
}]
});
`

$3

`ts
import { MessageHandlerBase, LogLevel, LoggerBuilder, LoggerConfigurationBuilder } from "simplr-logger";

class MyMessageHandler extends MessageHandlerBase {
public HandleMessage(level: LogLevel, timestamp: number, messages: any[]): void {
console.log(...messages);
}
}

const config = new LoggerConfigurationBuilder()
.AddWriteMessageHandler({ Handler: new MyMessageHandler(), LogLevel: LogLevel.Trace })
.Build();

const logger = new LoggerBuilder(config);

`

$3

#### Logging with methods

`ts
logger.Critical("Critical", "message");
logger.Debug("Debug", "message");
logger.Error("Error", "message");
logger.Info("Info", "message");
logger.Warn("Warn", "message");
logger.Trace("message", "with trace");
`

#### Logging with log level

`ts
logger.Log(LogLevel.Information, "Info message");
logger.Log(LogLevel.Critical, new Error("Critical error"));
`

#### Updating configuration

`ts
// Using old configuration
logger.UpdateConfiguration(builder => builder.SetPrefix("[new prefix]").Build());

// Or with default configuration
logger.UpdateConfiguration(builder => builder.SetPrefix("[new prefix]").Build(), false);
`

API

$3

| Name | Value | Description |
|-------------|:-----:|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| None | 0 | Not used for writing log messages. Specifies that a logging category should not write any messages. |
| Critical | 1 | Logs that describe an unrecoverable application or system crash, or a catastrophic failure that requires immediate attention. | |
| Error | 2 | Logs that highlight when the current flow of execution is stopped due to a failure. These should indicate a failure in the current activity, not an application-wide failure. |
| Warning | 4 | Logs that highlight an abnormal or unexpected event in the application flow, but do not otherwise cause the application execution to stop. |
| Information | 8 | Logs that track the general flow of the application. These logs should have long-term value. |
| Debug | 16 | Logs that are used for interactive investigation during development. These logs should primarily contain information useful for debugging and have no long-term value. |
| Trace | 32 | Logs that contain the most detailed messages. These messages may contain sensitive application data. These messages are disabled by default and should never be enabled in a production environment. |

$3

| Name | Default value | Description |
|-----------------------|----------------------------------------------------------------------------|--------------------------------------------------------------------|
| WriteMessageHandlers | [{ Handler: new ConsoleMessageHandler() }] | Message handlers list. ⁽¹⁾ |
| DefaultLogLevel | { LogLevel: LogLevel.Warning, LogLevelIsBitMask: false } | Log level or log levels in bit mask value. |
| Prefix | undefined | Custom message, which will be injected into the start of messages. |

(1)` - The default value is only available if configuration property is not set.

License

Released under the MIT license.