Debugging with printh

This recipe shows how to use PICO-8's printh() function to output debug information to your terminal.

Setup

Enable pipeOutputToConsole in your config:

// jspicl.config.ts
import type {Config} from "@jspicl/cli/types";

const config: Config = {
  pipeOutputToConsole: true,
  spritesheetImagePath: "assets/sprites.png",
  jsOutput: "build/game.js"
  // ...
};

export default config;

Usage

Use printh() anywhere in your game code:

function _update() {
  if (btn(0)) {
    player.x -= 1;
    printh("Player moved left: " + player.x);
  }
}

Output

When running in watch mode, you'll see the output in your terminal:

Player moved left: 63
Player moved left: 62
Player moved left: 61

Tips

• Use printh() for debugging values that change frequently (positions, states, etc.)
• Unlike print(), printh() doesn't appear on the PICO-8 screen
• Combine with watch mode for a rapid debug-fix-test cycle
• Remove or comment out printh() calls before publishing your game to avoid unnecessary overhead