Group By Category

ROSETTA STONE

Planned

ROSETTA 07 — Implementation Comparison
Compare grouping algorithms using the same project data.

Rosetta Stone Group By Category Preview coming soon

ROSETTA 07

Rosetta Stone Group By Category

Comparison Contract

Build keyed groups from repeated category values and render grouped results.

Comparison Contract

Build keyed groups from repeated category values and render grouped results.

Objective & Comparison Rule

Build each implementation without changing the shared behavior or visual target.

Rosetta Contract

Objective

Compare grouping algorithms using the same project data.

Comparison Rule

Build keyed groups from repeated category values and render grouped results.

Keep equivalent input, behavior, and visible output in every later language version.

Implementation Plan

Keep the comparison surface fixed while language syntax and runtime details change.

Structure

project/
├── input/
│   └── fixture.json
├── expected/
│   └── output.json
├── package.json
├── tsconfig.json
├── index.html
├── styles.css
└── src/
    └── app.ts

Initial Implementation

JavaScript / modern ECMAScript
HTML
CSS
JSON

Comparison Languages

JavaScript / modern ECMAScript
TypeScript
Angular
Python
Java
C#
PHP

Source Learning Project

Source Learning Project — TypeScript Project: Group By Category Board

src/generator/generate.ts → groupRecordsByCategory()

Technologies

JavaScript / modern ECMAScript

TypeScript

Angular

Python

Java

PHP

Build Instructions

Start with the first technology listed under Technologies, then reproduce the same behavior in each following implementation.

Freeze the Contract

Define the exact input, visible behavior, and expected output.

Build Initial Implementation

Implement the reference version with the same standalone visual layer.

Later Comparison

Rebuild without changing the contract.

TypeScript Implementation Reference

This implementation becomes the first concrete Rosetta comparison point.

Reference Code

Use the same input when building later language versions.

const groups = new Map<string, Project[]>();

for (const project of projects) {
  const key = project.category;
  const group = groups.get(key) ?? [];
  group.push(project);
  groups.set(key, group);
}

TypeScript Implementation Configuration

Keep the TypeScript implementation independently buildable; each implementation should keep its own required setup.

package.json

{
  "type": "module",
  "scripts": { "build": "tsc" },
  "devDependencies": { "typescript": "^7.0.2" }
}

tsconfig.json

{
  "compilerOptions": {
    "rootDir": "./src",
    "outDir": "./dist",
    "target": "ES2022",
    "module": "ES2022",
    "lib": ["ES2022", "DOM"],
    "strict": true,
    "sourceMap": true
  },
  "include": ["src/**/*.ts"]
}

Comparison Dimensions

Record differences that teach language and runtime behavior rather than cosmetic syntax.

Compare

Syntax and data declarations
Typing and validation
Collections and standard-library operations
Modules and file organization
Runtime and build requirements
Database or HTTP APIs when applicable
Visible output and behavioral equivalence