deno-logger

Deno / NodeJS colorful logger colorful logger

For Deno usage refer to deno-logger doc

Useage

console logger

import { Logger } from "jsr:@deno-library/logger";
// or
// import Logger from "https://deno.land/x/logger@v1.1.7/logger.ts";

const logger = new Logger();

logger.info("i am from consoleLogger", { name: "zfx" });
logger.warn("i am from consoleLogger", 1, "any");
logger.error("i am from consoleLogger", new Error("test"));

file and console logger

import { Logger } from "jsr:@deno-library/logger";
// or
// import Logger from "https://deno.land/x/logger@v1.1.7/logger.ts";

const logger = new Logger();

// console only
logger.info("i am from consoleLogger", { name: "zfx" });
logger.warn("i am from consoleLogger", 1, "any");
logger.error("i am from consoleLogger", new Error("test"));

await logger.initFileLogger("../log");

// file and console
logger.info("i am from fileLogger", { name: "zfx" });
logger.warn("i am from fileLogger", 1, "any");
logger.error("i am from fileLogger", new Error("test"));

file logger only

import { Logger } from "jsr:@deno-library/logger";
// or
// import Logger from "https://deno.land/x/logger@v1.1.7/logger.ts";

const logger = new Logger();
await logger.initFileLogger("../log");
logger.disableConsole();

// file only
logger.info(["i am from fileLogger", 1], { name: "zfx" });

file logger optional parameter

interface

interface fileLoggerOptions {
  rotate?: boolean; // cut by day
  maxBytes?: number;
  // Only available if maxBytes is provided, Otherwise you will get an error
  maxBackupCount?: number;
}

example

import { Logger } from "jsr:@deno-library/logger";
// or
// import Logger from "https://deno.land/x/logger@v1.1.7/logger.ts";

const logger = new Logger();

// cut by day
// filename is [date]_[type].log
// example 2020-05-25_warn.log, 2020-05-25_info.log, 2020-05-25_error.log
await logger.initFileLogger("../log", {
  rotate: true,
});

// maxBytes
// filename is [type].log.[timestamp]
// example: info.log.1590374415956
await logger.initFileLogger("../log", {
  maxBytes: 10 * 1024,
});

// rotate and maxBytes
// filename is [date]_[type].log.[timestamp]
// example: 2020-05-25_info.log.1590374415956
await logger.initFileLogger("../log", {
  rotate: true,
  maxBytes: 10 * 1024,
});

// maxBytes and maxBackupCount
// filename is [type].log.[n]
// example info.log.1, info.log.2 ...
// when reach maxBackupCount, the [type].log.[maxBackupCount-1] will be overwrite
//  detail:
// `maxBytes` specifies the maximum size
// in bytes that the log file can grow to before rolling over to a new one. If the
// size of the new log message plus the current log file size exceeds `maxBytes`
// then a roll over is triggered. When a roll over occurs, before the log message
// is written, the log file is renamed and appended with `.1`. If a `.1` version
// already existed, it would have been renamed `.2` first and so on. The maximum
// number of log files to keep is specified by `maxBackupCount`. After the renames
// are complete the log message is written to the original, now blank, file.
//
// Example: Given `log.txt`, `log.txt.1`, `log.txt.2` and `log.txt.3`, a
// `maxBackupCount` of 3 and a new log message which would cause `log.txt` to
// exceed `maxBytes`, then `log.txt.2` would be renamed to `log.txt.3` (thereby
// discarding the original contents of `log.txt.3` since 3 is the maximum number of
// backups to keep), `log.txt.1` would be renamed to `log.txt.2`, `log.txt` would
// be renamed to `log.txt.1` and finally `log.txt` would be created from scratch
// where the new log message would be written.
await logger.initFileLogger("../log", {
  maxBytes: 10 * 1024,
  maxBackupCount: 10,
});

// rotate and maxBytes and maxBackupCount
// filename is [date]_[type].log.[n]
// example 2020-05-25_info.log.1, 2020-05-25_info.log.2
// when reach maxBackupCount, the [type].log.[maxBackupCount-1] will be overwrite
await logger.initFileLogger("../log", {
  rotate: true,
  maxBytes: 10 * 1024,
  maxBackupCount: 10,
});

// rotate and maxBackupCount
// maxBackupCount will be ignored
await logger.initFileLogger("../log", {
  rotate: true,
  maxBackupCount: 10,
});

The following conditions will throw an error

// maxBackupCount
// get error => maxBackupCount must work with maxBytes
await logger.initFileLogger("../log", {
  maxBackupCount: 10,
});
// rotate and maxBackupCount
// get error => maxBackupCount must work with maxBytes
await logger.initFileLogger("../log", {
  rotate: true,
  maxBackupCount: 10,
});

disableConsole and enableConsole

import { Logger } from "jsr:@deno-library/logger";
// or
// import Logger from "https://deno.land/x/logger@v1.1.7/logger.ts";

const logger = new Logger();

// console
logger.info("console enabled, you can see me");
logger.disableConsole();
// no message is logged
logger.info("console disabled");
logger.enableConsole();
// console
logger.info("console enabled, you can see me");

disableFile and enableFile

import { Logger } from "jsr:@deno-library/logger";
// or
// import Logger from "https://deno.land/x/logger@v1.1.7/logger.ts";

const logger = new Logger();
await logger.initFileLogger("../log");

logger.disableFile();
// not log to file
logger.info("file disbaled");
logger.enableFile();
// log to file
logger.info("file enabled, you can see me");

disable and enable

disable disable write to file and terminal, don’t care if it is currently writing to a file or terminal, but hope to restore the currently configuration later
enable restore previous log configuration: file, terminal or both

example:

fileLogger => disable => enable => fileLogger
consoleLogger => disable => enable => consoleLogger
fileLogger, consoleLogger => disable => enable => fileLogger, consoleLogger

import { Logger } from "jsr:@deno-library/logger";
// or
// import Logger from "https://deno.land/x/logger@v1.1.7/logger.ts";

const logger = new Logger();
await logger.initFileLogger("../log");

logger.disable();
logger.enable();

test

deno test --allow-read --allow-write

Dual-Stack / Triple-Stack integration

A dual-stack project is generaly a npm project that can be import as commonJS module or as ESM module; So if a project can also be import as a Deno module, it’s a triple-stack one.

To convert your Deno project to a dual-stack npm project, you should use deno/dnt, then create a _build_npm.ts or scripts/build_npm.ts that looks like:

import { build, emptyDir } from "@deno/dnt";

// grap the next version number as you want
const version: Deno.args[0];
await emptyDir("./npm");
await build({
  entryPoints: ["./mod.ts"],
  outDir: "./npm",
  shims: {
    deno: true,
  },
  compilerOptions: {
    lib: ["dom", "esnext"],
  },
  package: {
    name: "pkg-name",
    version: version,
    // ... package stuff
  },
  // map your favorite deno logger to its npm port.
  mappings: {
    "https://deno.land/x/logger@v1.1.7/logger.ts": {
      name: "@denodnt/logger",
      version: "1.1.7",
      peerDependency: false,
    },
  },
});

Screenshots

consoleLogger

fileLogger

cut logs by day
CutByDay

More screenshots in the screenshots folder.

Logger interface

interface fileLoggerOptions {
  rotate?: boolean;  // cut by day
  maxBytes?: number, // the maximum size in bytes that the log file can grow to before rolling over to a new one
  maxBackupCount?: number // maxBackupCount must work with maxBytes
}

interface LoggerInerface {
  constructor()

  info(...args: unknown[]): void
  warn(...args: unknown[]): void
  error(...args: unknown[]): void

  async initFileLogger(dir: string, options: fileLoggerOptions = {}): Promise<void>

  disableConsole(): void
  enableConsole(): void

  disableFile(): void;
  enableFile(): void;

  disable(): void;
  enable(): void;
}