Learn Deno-playground - 10 Code Examples & CST Typing Practice Test

Deno Playground is a web-based platform for writing, running, and sharing Deno scripts directly in the browser. It allows developers to experiment with Deno's modern JavaScript and TypeScript runtime without local installation.

View all 10 Deno-playground code examples →

Hello World in Deno Playground (TypeScript)Deno Playground HTTP Server Deno Playground File Read Example Deno Playground Fetch Example Deno Playground Write File Example Deno Playground Environment Variables Deno Playground Path Example Deno Playground Timer Example Deno Playground Command Line Args Deno Playground JSON File Example

Learn DENO-PLAYGROUND with Real Code Examples

Updated Nov 26, 2025

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Code Sample Descriptions

Hello World in Deno Playground (TypeScript)

console.log("Hello World");

A simple Hello World program written and run in Deno Playground using TypeScript.

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Deno Playground HTTP Server

import { serve } from "https://deno.land/std@0.203.0/http/server.ts";

serve(req => new Response('Hello World', { status: 200 }));

A basic HTTP server using Deno that responds with 'Hello World'.

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Deno Playground File Read Example

const data = await Deno.readTextFile('example.txt');
console.log(data);

Reads a local text file and prints its contents to the console.

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Deno Playground Fetch Example

const res = await fetch('https://api.github.com');
const data = await res.json();
console.log(data);

Fetches data from a public API and prints JSON response.

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Deno Playground Write File Example

await Deno.writeTextFile('output.txt', 'Hello Deno');
console.log('File written!');

Writes text into a file using Deno.

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Deno Playground Environment Variables

const value = Deno.env.get('MY_VAR') || 'Not set';
console.log(value);

Accesses an environment variable and prints its value.

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Deno Playground Path Example

import { join } from "https://deno.land/std@0.203.0/path/mod.ts";
const path = join('folder', 'file.txt');
console.log(path);

Uses Deno's path module to join paths.

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Deno Playground Timer Example

let count = 0;
const interval = setInterval(() => {
    console.log(`Tick: ${count}`);
    count++;
    if(count>5) clearInterval(interval);
}, 1000);

Shows a simple interval timer that prints every second.

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Deno Playground Command Line Args

console.log(Deno.args);

Prints command line arguments passed to the script.

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Deno Playground JSON File Example

const json = await Deno.readTextFile('data.json');
const obj = JSON.parse(json);
console.log(obj);

Reads a JSON file and logs its parsed contents.

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Frequently Asked Questions about Deno-playground

What is Deno-playground?

What are the primary use cases for Deno-playground?

Learning Deno programming online. Testing JavaScript/TypeScript scripts. Experimenting with Deno modules and features. Sharing reproducible examples in blogs, tutorials, or forums. Quick prototyping of small scripts or algorithms

What are the strengths of Deno-playground?

No local installation required. Immediate feedback from executed code. Safe sandbox environment for testing scripts. Ideal for learning and experimentation. Shareable examples simplify collaboration

What are the limitations of Deno-playground?

Limited to small scripts; not suitable for full projects. No persistent storage for scripts. Cannot host web servers or long-running services. Restricted runtime environment. Some Node.js-specific APIs not supported

How can I practice Deno-playground typing speed?

CodeSpeedTest offers 10+ real Deno-playground code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

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Code Sample Descriptions

Hello World in Deno Playground (TypeScript)

console.log("Hello World");

A simple Hello World program written and run in Deno Playground using TypeScript.

Let’s Try →

Deno Playground HTTP Server

import { serve } from "https://deno.land/std@0.203.0/http/server.ts";

serve(req => new Response('Hello World', { status: 200 }));

A basic HTTP server using Deno that responds with 'Hello World'.

Let’s Try →

Deno Playground File Read Example

const data = await Deno.readTextFile('example.txt');
console.log(data);

Reads a local text file and prints its contents to the console.

Let’s Try →

Deno Playground Fetch Example

const res = await fetch('https://api.github.com');
const data = await res.json();
console.log(data);

Fetches data from a public API and prints JSON response.

Let’s Try →

Deno Playground Write File Example

await Deno.writeTextFile('output.txt', 'Hello Deno');
console.log('File written!');

Writes text into a file using Deno.

Let’s Try →

Deno Playground Environment Variables

const value = Deno.env.get('MY_VAR') || 'Not set';
console.log(value);

Accesses an environment variable and prints its value.

Let’s Try →

Deno Playground Path Example

import { join } from "https://deno.land/std@0.203.0/path/mod.ts";
const path = join('folder', 'file.txt');
console.log(path);

Uses Deno's path module to join paths.

Let’s Try →

Deno Playground Timer Example

let count = 0;
const interval = setInterval(() => {
    console.log(`Tick: ${count}`);
    count++;
    if(count>5) clearInterval(interval);
}, 1000);

Shows a simple interval timer that prints every second.

Let’s Try →

Deno Playground Command Line Args

console.log(Deno.args);

Prints command line arguments passed to the script.

Let’s Try →

Deno Playground JSON File Example

const json = await Deno.readTextFile('data.json');
const obj = JSON.parse(json);
console.log(obj);

Reads a JSON file and logs its parsed contents.

Let’s Try →

Frequently Asked Questions about Deno-playground

What is Deno-playground?

What are the primary use cases for Deno-playground?

What are the strengths of Deno-playground?

No local installation required. Immediate feedback from executed code. Safe sandbox environment for testing scripts. Ideal for learning and experimentation. Shareable examples simplify collaboration

What are the limitations of Deno-playground?

How can I practice Deno-playground typing speed?

CodeSpeedTest offers 10+ real Deno-playground code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.