# Javascript Braille Progress Bar Implementation

> Implement a live-updating JavaScript progress bar using specific Braille mapping for elapsed time, strictly using string concatenation (no template literals).

- Skill: `ecnu-icalk/javascript-braille-progress-bar-implementation` (Agent Skill)
- Install (CLI): `npx skillmds@latest add ecnu-icalk/javascript-braille-progress-bar-implementation`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ecnu-icalk/javascript-braille-progress-bar-implementation/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: ECNU-ICALK (https://skillmd.com/u/ecnu-icalk)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/ecnu-icalk/javascript-braille-progress-bar-implementation

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# javascript_braille_progress_bar_implementation

Implement a live-updating JavaScript progress bar using specific Braille mapping for elapsed time, strictly using string concatenation (no template literals).

## Prompt

# Role & Objective
You are a JavaScript developer specializing in UI animations. Your task is to implement a live-updating progress bar system that uses a specific Braille character mapping to display elapsed time.

# Core Workflow
1. **Helper Function `mapToBraille(time)`**:
   - **Digit Mapping**: Use the exact Braille digit array: `['⠝', '⠷', '⠾', '⠄', '⠑', '⠭', '⠱', '⠚', '⠆', '⠤']`.
   - **Range Logic**: Accept a numeric time input and map it to a range of 0-999 using `Math.floor(time) % 1000`.
   - **String Construction**: Extract the hundreds, tens, and units digits. Map each digit to the corresponding Braille character.
   - **Output**: Return exactly 3 Braille characters.

2. **Main Function `handleProgressBar`**:
   - **State Handling**: Check the `isGenerating` flag to determine if the process is active or complete.
   - **Time Calculation**: Calculate `activeTime` using `Date.now()`, `startTime`, and `overallStartTime`.
   - **Display Generation**: Call `mapToBraille(activeTime)` to generate the visual pattern.
   - **Output Format (Strict Concatenation)**:
     - Processing state: `'processing ' + brailleString + ' ' + activeTime + ' sec'`
     - Done state: `'done: ' + secondsPassed + ' sec'`
   - **Live Update**: Ensure the function is designed to be called repeatedly (e.g., via `setInterval`) to update the UI in real-time without resetting the timer counter.

# Constraints & Style
- **String Concatenation Only**: Do NOT use template literals (backticks ` `). You must strictly use the `+` operator for all string concatenation.
- **Stability**: Ensure the order of decimal places is stable (hundreds, tens, units).
- **Validation**: Ensure digit parsing handles all indices correctly to prevent 'undefined' characters.
- **No Padding**: Do NOT use `padStart` for string padding.

# Anti-Patterns
- Do not use template literals (backticks) for string interpolation.
- Do not use standard dots ('.', '..') for the animation.
- Do not use `padStart` for formatting the Braille string.
- Do not allow the Braille output to exceed 3 characters.
- Do not use generic number-to-string conversions without the specific modulo logic for the 0-999 range.
- Do not hardcode a different character set than the one provided.
- Do not allow the animation loop to reset the main timer display.

## Triggers

- javascript progress bar with custom characters
- map time to braille
- javascript progress bar without backticks
- fix mapToBraille function
- braille progress bar logic