The logger of the Remus Application Framework that is also usable in an independent manner.
Create a logger and log to it:
import { l } from "@remus/log";
const log = l("mycode.file"); // sets the code reference information to this logger instance
log.error("this is my first error message"); //creates a log message and propagates it to the appenders specified
//the output could look like this
[timestamp][ERROR][mycode.file] this is my first error message
Providing more information to be logged:
import { l, Categories } from "@remus/log";
const log = l("mycode.file", Categories.IO, "client"); //sets also the category and origin properties of the logger instance
log.id("id").category(".rest").ref("handlerclass").origin("webworker").warn("this is a warning"); //specifies multiple properties for the new message, properties set to the logger are propagated to the message
//the output could look like this
[timestamp][client/webworker][ WARN][id][IO.rest][mycode.file:handlerclass] this is a warning
Logging things once:
import { l } from "@remus/log";
const log = l("mycode.file");
log.once().trace("a config should be provided"); // this message will be propagated once with the same log level (trace)
log.once("a unique id").trace("a config should be provided"); // a call using the same once-id will be logged once independently from other message properties
log.id("message-id").once().fatal("a config should be provided"); // only one message using the same id and log level will be logged
Providing dynamic message parameters:
import { l } from "@remus/log";
const log = l("mycode.file");
log.debug("parameter '%parameter%' with value '%value%' is not acceptible, try %mitigations.a%", {parameter = "XY", value = 0.5, mitigations : { a : "test"}});
const e = new Error("E_ILLEGAL");
log.error("an error occurred: %e.message% at %e.stack%", {e});
Configuring the appenders:
import { Logger, Severity } from "@remus/log";
import { ColourConsoleAppender, FileAppender, Filters } from "@remus/log/appenders";
Logger.addAppender(new ColourConsoleAppender()); //logs coloured console output
let fileAppender = new FileAppender();
Logger.addAppender(fileAppender); //logs to a .log file in the current working directory
fileAppender.addFilter(Filters.SEVERITY_MIN(Severity.INFO)); //add a filter to the file appender in order only to log info and above messages
Add a fallback appender that catches all not logged messages and errors from the log framework as well as disable the internal log message cache for unappended messages:
import { Logger , setRootLoggerProperties } from "@remus/log";
import { VoidAppender } from "@remus/log/appenders";
//add a catch all appender as fallback
Logger.addFallBackAppender(new VoidAppender());
//or disable the cache manually
setRootLoggerProperties(true);
This is only basic usage information, see Source Code Documentation or Remus Homepage for more.
The following components are used for developing:
tsconfig.json and tsconfig.spec.json (for testing) both inheriting from tsconfig.base.json. The configuration is rather restricting focusing on modern environments. In some cases, e.g. a function in a class that shall be implemented by subclasses while declaring parameters, certain rules may be locally overridden, in this case, to allow unused parameters. Call npm run build to generate the JavaScript sources including map and d.ts files in the ./build directory.eslint.config.js. While linting is done prior to building, it is useful to enable an eslint plugin in the IDE. Eslint is configured for the use of typescript../test using the *.spec.ts file name pattern. Test are built and executed automatically when calling npm run test.Debug Test launch configuration for that and place breakpoints in the *.ts sources or *.spec.ts test sources../reports directory as html). Run npm run coverage for generating the reports. Open /reports/coverage/index.html in a browser to read the interactive documentation.npm run docs for generating them. Open docs/index.html in a browser to read the documentation.