@m234/logger

A colorful logger with the ability to log "Processing ... done".

Features

• Interactive Task Tracking: Display ongoing tasks with spinners and status indicators.
• Automatic Console Hooking: Intercepts console.log and other output to prevent them from breaking the task display.
• Cross-Platform: Works seamlessly in both Deno and Node.js.
• Indented Subtasks: Organize complex operations with hierarchical task structures.
• Customizable: Configure prefixes, colors, and duration displays.

Usage

Simple printing

Basic logging and formatted output for your application:

import { format, Logger } from "@m234/logger";

const logger = new Logger({ prefix: "MyApp" });

logger.print("Hello, World!");
logger.println("Hello, World!");
logger.print(format("Hello, World! %o", true));

logger.info("This is an informational message.");
logger.warn("This is a warning.");
logger.error("This is an error.");
logger.success("This is a success message.");

Task printing

Track the progress and result of long-running or multi-step operations. Task printing provides visual feedback for ongoing, successful, skipped, failed, or aborted tasks:

import { Logger } from "@m234/logger";

const logger = new Logger({ prefix: "MyApp" });
using task = logger.task({
  text: "Operating",
  disposeState: "completed",
  // defaultTaskOptions: { suffixDuration: false }
}).start();

// Output: - MyApp Operating ...
task.end("completed");
// Output: ✓ MyApp Operating ... done
task.end("skipped");
// Output: ✓ MyApp Operating ... skipped
task.end("failed");
// Output: ✗ MyApp Operating ... failed
task.end("aborted");
// Output: ⚠ MyApp Operating ... aborted

Task runner

Automate task execution and handle asynchronous operations with task runners. This feature allows you to run a function as a task, automatically updating the task status based on the function's result:

import { Logger } from "@m234/logger";
import { delay } from "jsr:@std/async/delay";

const logger = new Logger({ prefix: "MyApp" });
logger.task({
  text: "Operating",
}).startRunner(async ({ task }) => {
  await delay(1000);
  return "completed";
});

Subtasks

You can create hierarchical tasks using the indent option:

const parent = logger.task({ text: "Main operation" }).start();
const subtask = logger.task({ text: "Sub-operation", indent: 1 }).start();

await delay(500);
subtask.end("completed");
parent.end("completed");

Automatic Console Hooking

When tasks are active, the library automatically hooks into console.log, process.stdout.write, and Deno's output streams. Any output sent through these methods will be "persisted" above the active tasks, ensuring that the interactive task display remains at the bottom of the terminal.

API Reference

LoggerOptions

Option	Type	Default	Description
prefix	string	-	A string to prefix all logging methods.
disabled	boolean	false	Whether logging is disabled.
defaultTaskOptions	DefaultTaskOptions	-	Default options for all tasks created by this logger.

TaskOptions

Option	Type	Default	Description
text	string	-	The text to display for the task.
state	TaskState	"idle"	Initial state of the task.
disposeState	TaskStateEnd	"completed"	Final state when the task is disposed.
indent	number	0	Indentation level of the task.
suffixDuration	boolean | bigint	false	Whether to show the task duration. If a bigint is provided, the duration is shown live if it's more than the threshold.
interactive	boolean	true	Whether the task rendering shouldn't be simplified.

More examples

• scripts/example-ora.ts: Demonstrates integrating the logger with the ora spinner for animated task progress, updating the spinner frame in real time and marking the task as completed after a delay.
• scripts/example-ora-suffix.ts: Shows a custom Task class that appends an ora spinner animation as a suffix to the task text, including multiple tasks and subtasks with different completion states.
• scripts/example-stress.ts: Runs a stress test by creating and updating the state of 20 tasks in rapid succession, randomly changing their states to simulate heavy usage and concurrent task updates.
• scripts/example-persists.ts: Uses console.log and stdout.write while there are spinning tasks.