TypeScript Lab: ROLLBACK Simulator

LAB / EXPLORATION

TypeScript Lab: ROLLBACK Simulator

Planned

LAB 113 — Database Transactions
Trigger an error and visibly restore pre-transaction data.

LAB TypeScript Lab: ROLLBACK Simulator Preview coming soon

LAB 113

TypeScript Lab: ROLLBACK Simulator

Concept

Rollback cancels uncommitted changes when an operation cannot finish safely.

Concept

Rollback cancels uncommitted changes when an operation cannot finish safely.

Objective & Explanation

What the project should make visible and why the concept matters.

Learning Target

Objective

Trigger an error and visibly restore pre-transaction data.

Explanation

Rollback cancels uncommitted changes when an operation cannot finish safely.

Project Plan

Structure, technologies, data boundary, and source connection.

Structure

project/
├── package.json
├── tsconfig.json
├── index.html
├── styles.css
├── data/
│   └── learning.db
└── src/
    ├── client.ts
    └── server.ts

Technologies

TypeScript
Node.js
SQLite
HTML
CSS

Data Layer

Use SQLite learning rows. Isolate destructive practice from important Sandbox records.

Sandbox Source

src/local-editor/server.ts

Build Instructions

Build only the focused behavior, then use the visual layer to inspect it.

Setup

Create the standalone project folder and listed files.

Implement

Implement the smallest version that demonstrates the concept.

Run & Inspect

Render the returned or changed data in the browser.

Code & Configuration

Starter configuration plus the focused implementation example.

Focused TypeScript

Implement this behavior first, then alter the input.

database.exec("BEGIN;");
try {
  makeChanges();
  throw new Error("Simulated failure");
} catch {
  database.exec("ROLLBACK;");
}

Starter Configuration

Keep the project independently buildable.

package.json

{
  "type": "module",
  "scripts": {
    "build": "tsc",
    "start": "npm run build && node --enable-source-maps dist/server.js"
  },
  "devDependencies": {
    "@types/node": "^26.4.0",
    "typescript": "^7.0.2"
  }
}

tsconfig.json

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

Expected Visual Result

The output is the proof that the concept is working.

Visible Proof

The browser should visibly demonstrate: trigger an error and visibly restore pre-transaction data.

Data: SQLite