HoverLookup

Instantly see what those IDs, codes, and numbers mean by hovering over them.

Stop switching between your code and database queries. Supported databases:

• Local JSON database:
  

• MongoDB:
  

Works in the debugger too:

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Why HoverLookup?

Ever found yourself staring at code like this?

const user = getUser(12345);
processOrder("ORD-2024-ABC");

What does 12345 mean? Who is that user? What's in order ORD-2024-ABC?

With HoverLookup, you hover and instantly see:

{
  "id": 12345,
  "name": "Sarah Johnson",
  "email": "sarah@example.com",
  "role": "admin"
}

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Key Features

Hover Over Anything

• Literals: Hover over 1, "abc", or any value in your code (works in any language)
• Variables: Hover over variables during debugging to see their runtime value + database info
• Language support: Literals work everywhere; variable analysis optimized for JavaScript/TypeScript

Smart & Flexible

• Dynamic ID field: Use id, userId, code, sku, or any field as your lookup key
• Auto-reload: Database updates automatically when your JSON file changes
• Debug integration: Works seamlessly with VSCode's debugger
• MongoDB support: Query MongoDB collections on-demand (configurable per collection)

Multiple databases

• Local JSON database
• MongoDB

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Quick Start for local JSON database

1. Initialize the Database

Open the Command Palette (Ctrl+Shift+P / Cmd+Shift+P) and run:

HoverLookup: Initialize Database

This creates a lookup-database.json file with an example structure.

2. Add Your Data

Edit the JSON file with your own data. You can use a single field or multiple fields for lookups:

Single ID field:

{
  "idField": "id",
  "data": [
    {"id": 1, "name": "John Doe", "email": "john@example.com"},
    {"id": 2, "name": "Jane Smith", "email": "jane@example.com"}
  ]
}

Multiple ID fields (mix different object types):

{
  "idField": ["id", "userId", "code"],
  "data": [
    {"id": 1, "name": "John Doe", "role": "admin"},
    {"userId": 42, "name": "Jane Smith", "department": "Engineering"},
    {"code": "ORD-2024-001", "status": "shipped", "total": 299.99}
  ]
}

When using multiple fields, the extension will try each field in order until it finds a value.

3. Start Hovering!

const userId = 1;              // Hover over "1" → see John Doe's info
const employee = 42;           // Hover over "42" → see Jane Smith's info
const order = "ORD-2024-001";  // Hover over "ORD-2024-001" → see order details

Quick Start for MongoDB

1. Configure MongoDB Connection

Open your VSCode settings and add your MongoDB connection URL:

{
  "hoverLookup.mongodbUrl": "mongodb://localhost:27017"
}

2. Configure Collections to Search

Add the collections you want to search in your MongoDB database:

{
  "hoverLookup.mongodbCollections": [
    {
      "collection": "users",
      "searchFields": ["id", "email"],
      "project": {
        "name": 1,
        "email": 1,
        "status": 1
      }
    },
    {
      "collection": "products",
      "searchFields": ["sku", "code"],
      "project": {
        "name": 1,
        "price": 1,
        "stock": 1
      }
    }
  ]
}

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Advanced Configuration

Custom Database Path

Set a custom path in your VSCode settings:

{
  "hoverLookup.databasePath": "data/my-custom-db.json"
}

The extension will try each field in order until it finds a match.

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How It Works

HoverLookup operates in two modes:

• Normal Editing Mode

  • Detects literals and variables using static analysis, then looks them up in your databases.

• Debug Mode

  • Intercepts the debugger's variable evaluation, extracts runtime values, and enriches the hover with databases information.

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Architecture

Built with a clean, modular structure for maintainability and extensibility:

graph TD
    A[extension.js<br/>Main Entry Point] --> B[utils/database.js<br/>Database Management]
    A --> C[providers/hoverProvider.js<br/>Hover Provider]
    A --> D[adapters/debugAdapter.js<br/>Debug Adapter]
    A --> E[utils/commands.js<br/>Command Registration]

    C --> B
    C --> F[utils/parser.js<br/>String/Number Parsing]
    C --> G[utils/variableResolver.js<br/>Variable Resolution]

    D --> B
    E --> B
    G --> H[VS Code Debug API]

    style A fill:#4CAF50,color:#fff
    style B fill:#2196F3,color:#fff
    style C fill:#FF9800,color:#fff
    style D fill:#9C27B0,color:#fff
    style E fill:#2196F3,color:#fff
    style F fill:#2196F3,color:#fff
    style G fill:#2196F3,color:#fff

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Known Limitations

• Literal detection (strings, numbers) works in all languages
• Variable static analysis is optimized for JavaScript/TypeScript syntax (const, let, var)
• For other languages or complex expressions, use the debugger for accurate variable lookups
• Static analysis only works for simple assignments in the same file