Online TypeScript Compiler – Run TypeScript in Your Browser

Use our online TypeScript compiler to write, compile, and run TypeScript code instantly in the browser. Perfect for developers learning TypeScript or testing code on the fly.

Version

Sample

🚀 total executions ( this month)

💡 Learn Typescript to upgrade your skills

💡 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();