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Demystifying the Deno Standard Library

By David Li on 2023-10-18T14:25:14.000Z

Demystifying the Deno Standard Library

Deno, a secure runtime for JavaScript and TypeScript, has been gaining traction in recent years due to its focus on security, developer-friendly features, and modern tooling. One of the key components of Deno is its standard library, which offers a collection of high-quality, well-maintained modules that come with the runtime itself. In this article, we’ll explore the Deno standard library and how it contributes to the overall Deno ecosystem.

What is the Deno Standard Library?

The Deno standard library is a curated set of modules that are designed to work seamlessly with the Deno runtime. These modules are written in TypeScript and cover a wide range of functionalities, from basic utilities to more complex modules handling file systems, networking, and more.

The primary goal of the standard library is to provide developers with a reliable, performant, and well-documented set of tools to build applications in Deno. The standard library is hosted on Deno’s official GitHub repository and can be found here.

Key Features

Some of the key features of the Deno standard library include:

  1. Quality Assurance: The standard library modules are thoroughly tested and reviewed before being included in the library, ensuring that developers can rely on their quality and stability.

  2. TypeScript Support: All modules in the standard library are written in TypeScript, providing type safety and better development experience when using these modules in TypeScript projects.

  3. No Dependencies: The modules in the standard library do not rely on external dependencies, reducing the risk of dependency-related issues and improving the overall security.

  4. Versioning: The standard library follows a strict versioning policy, making it easy for developers to manage dependencies and ensure compatibility between different versions of their projects.

Exploring the Modules

The Deno standard library offers a wide range of modules to cater to various development needs. Some of the popular modules include:

1. fs (File System)

The fs module provides a set of functions to work with the file system, including reading, writing, and manipulating files and directories. This module offers a promise-based API, making it easy to work with asynchronous file system operations.

import { readFileStr } from "https://deno.land/std/fs/mod.ts";

const content = await readFileStr("./example.txt");

2. http (HTTP)

The http module offers a collection of utilities for working with HTTP, including an HTTP server and client. It simplifies the process of creating and managing HTTP servers and provides a powerful yet easy-to-use API for handling HTTP requests and responses.

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

const server = serve({ port: 8000 });

for await (const req of server) {
  req.respond({ body: "Hello, world!\n" });

3. datetime (Date and Time)

The datetime module provides a set of utilities for working with dates and times. It offers several functions for parsing, formatting, and manipulating date and time values, making it easier to handle time-related tasks.

import { parse, format } from "https://deno.land/std/datetime/mod.ts";

const date = parse("2023-05-07", "yyyy-MM-dd");
console.log(format(date, "dd/MM/yyyy")); // Output: 07/05/2023

4. uuid (Universally Unique Identifier)

The uuid module offers a simple way to generate and validate UUIDs (Universally Unique Identifiers). It supports various UUID versions, including v1, v3, v4, and v5.

import { v4 } from "https://deno.land/std/uuid/mod.ts";

const myUuid = v4.generate();


The Deno standard library is a powerful collection of modules that simplifies common development tasks and serves as a solid foundation for building applications with the Deno runtime. With its focus on quality, security, and ease of use, the standard library is an indispensable resource for Deno developers.

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