Enable logging on your TS Project using decorators|annotations.
npm i @xeinebiu/ts-logger@1.1.21.1.1
- Export LogClass
1.1.0
- Add LogClass Decorator
1.0.1
- Fix module exports
1.0.0
- Initial Version
Setting the listner is necessary to enable the logging.
Logger.listener = {
// Return True to output the given [log], false otherwise
beforeLog: (log: Log, outputType: OutputType) => {
return true;
},
// The given [log] is printed
afterLog: (log: Log, outputType: OutputType) => {
},
// Apply different styles of [Log] and [outputType]
applyStyle: (log: Log, outputType: OutputType) => {
if (outputType === OutputType.log) {
return 'background: #8c7ae6; color: #2f3640; padding: 3px';
}
return true;
}
};To log any method, use @Method.Log() decorator and @Method.asyncLong() for Asynchronous Methods.
Assume we have a class called Demo and we want to log some methods on it.
class Demo {
@Method.log()
public add(...args: number[]): number {
let sum = 0;
args.forEach(x => sum += x);
return sum;
}
}Now, every time the method add(..args) is invoked, an output will result in console like the below
The decorator @Method.log() accepts an MethodLoggerOptions as single argument where we can configure the Logger
for each Method.
@Method.log({tag: 'Sum collection of numbers', args: true, importance: 1, printResult: true})
public add(...args : number[]) : number {
let sum = 0;
args.forEach(x => sum += x);
return sum;
}With the above configuration, we are about to see 2 logs for the same method call. First Log when the method is invoked,
and the second when Return.
Arguments can be printed partially also.
@Method.asyncLog({tag: 'Login', printResult: true, args: [0]})
public login(username : string, password : string ): Promise < boolean > {
return new Promise < boolean > ((resolve) => {
setTimeout(() => resolve(true), 1000);
});
}
Injector can be used when Logging from inside of method is needed. Inject as last argument, the Logger and set it
to optional.
@Method.log({inject: true})
public add(args : number[], logger? : Logger) : number {
logger.debug('Add method is called');
let sum = 0;
args.forEach(x => sum += x);
logger.params.data.result = sum;
logger.debug(`Total: ${sum}`);
return sum;
}
Filter of logs can be done from the Listener beforeLog() callback.
beforeLog: (log: Log, outputType: OutputType) => {
return log.data.importance ! > 2 && outputType === OutputType.debug;
},
...Outputs only the Logs with importance greater than
2and of typedebug
beforeLog: (log: Log, outputType: OutputType) => {
return log.data.tag === 'login';
},
...Outputs only the logs with the Tag
login
Depending on your needs, filter can be done on many ways as it needed.
xeinebiu