Enhancement: Add Comprehensive Node.js REPL Guide

[Nymphalys]

Add Comprehensive Node.js REPL Guide

The repository currently lacks detailed documentation about Node.js REPL usage and advanced features.

This enhancement will introduce a structured REPL section.

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📘 Topics to Cover

1. Basic REPL Usage

• Starting REPL (node)
• Evaluating expressions
• Variable persistence
• Multiline input

2. Built-in REPL Commands

• .help
• .exit
• .clear
• .save
• .load
• .editor mode

3. REPL for Debugging

• Testing small code snippets
• Checking APIs quickly
• Inspecting objects

4. Advanced REPL

• Custom REPL creation using repl module
• Injecting context variables
• Creating interactive CLI tools

5. Production Use Cases

• Quick JSON testing
• Prototype logic before adding to codebase
• Exploring libraries interactively

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📌 Goal

Convert REPL from a “basic concept” into a powerful developer productivity tool section.