TypeScript CLI Runner Online

Quickly test TypeScript code in a command-line-like environment—perfect for developers on the go.

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Sample

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🌀 About This TypeScript Online Executor

The CodeUtility TypeScript Executor lets you write and run TypeScript code directly in your browser — no compiler setup, Node.js installation, or local environment required. It runs real TypeScript code compiled to JavaScript inside a secure, sandboxed runtime.

This environment currently supports TypeScript 5.4, giving you access to the latest language features such as decorators, improved type inference, and modern ECMAScript support.

Whether you're learning TypeScript, testing utility functions, or experimenting with typing and interfaces, this tool provides a fast and interactive way to write, compile, and execute your code with instant feedback.

It’s perfect for developers who want to explore TypeScript’s type system or verify how TypeScript compiles to JavaScript without switching between editors or local terminals.

💡 How to Use This Tool

1. Choose the available TypeScript version (5.4) from the dropdown at the top of the editor.
2. Write or paste your TypeScript code in the editor area — including types, interfaces, and generics.
3. Click Run to compile and execute your code, viewing the output in the console below.
4. While running, a Stop button will appear — click it to terminate the process early.
5. Use Fix Code to automatically correct syntax or indentation issues.
6. After fixing, a Fixes button appears — click it to review recent corrections.
7. You can also Upload a local file to the editor or Download your current code.
8. Each execution runs up to 20 seconds before timing out for stability and fairness.

🧠 Tip: The TypeScript Executor automatically compiles your code to JavaScript behind the scenes — so you can test real execution behavior while benefiting from static typing and compile-time safety.

💡 TypeScript Basics Guide for Beginners

1. Declaring Variables

TypeScript allows static typing with let, const, and type annotations.

let x: number = 10;
const pi: number = 3.14;
let name: string = "Alice";
let isActive: boolean = true;

2. Conditionals (if / switch)

Use if, else if, and else for branching. switch handles multiple values.

let x = 5;
if (x > 0) {
  console.log("Positive");
} else if (x < 0) {
  console.log("Negative");
} else {
  console.log("Zero");
}

switch (x) {
  case 1:
    console.log("One");
    break;
  case 2:
    console.log("Two");
    break;
  default:
    console.log("Other");
}

3. Loops

Use for, while, and for...of for iteration.

for (let i = 1; i <= 5; i++) {
  console.log(i);
}

let i = 5;
while (i > 0) {
  console.log(i);
  i--;
}

4. Arrays

Use square brackets [] to define arrays.

let numbers: number[] = [1, 2, 3, 4, 5];
let names: string[] = ["Alice", "Bob"];
console.log(numbers[1]);

5. Array Manipulation

Use built-in methods like push, splice, and filter.

let arr = [10, 20, 30];
arr.push(40);          // Append
arr.splice(1, 1);      // Remove second element
console.log(arr);

6. Console Input/Output

Use console.log to display output in the console.

const name: string = "Alice";
console.log("Hello, " + name);

7. Functions

Declare functions with typed parameters and return values.

function add(a: number, b: number): number {
  return a + b;
}

console.log(add(3, 5));

8. Maps

Use plain objects or Map for key-value structures.

const m = new Map<string, number>();
m.set("Alice", 25);
console.log(m.get("Alice"));

9. Exception Handling

Use try and catch to handle errors.

try {
  throw new Error("Something went wrong");
} catch (e) {
  console.error(e.message);
}

10. File I/O (Node.js only)

Use Node.js fs module to read and write files.

import * as fs from "fs";

fs.writeFileSync("file.txt", "Hello File");
const content = fs.readFileSync("file.txt", "utf-8");
console.log(content);

11. String Manipulation

Use string methods like length, concat, includes.

let str = "Hello World";
console.log(str.length);
console.log(str + "!");
console.log(str.includes("World"));

12. Classes & Objects

TypeScript supports object-oriented programming.

class Person {
  name: string;
  constructor(name: string) {
    this.name = name;
  }
  greet() {
    console.log(\`Hi, I'm \${this.name}\`);
  }
}

const p = new Person("Alice");
p.greet();