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Deno

Ajeet Raina
Author
Ajeet Raina, Former Developer Growth Manager at Redis

With over 80,000 stars and 670+ contributors, Deno is a popular modern runtime for JavaScript and TypeScript. It is built on V8, an open-source JavaScript engine developed by the Chromium Project for Google Chrome and Chromium web browsers.

Features of Deno#

  • Deno is secure by default. It executes code in a sandbox environment, disallowing runtime access to the underlying filesystem, environment variables and scripts.
  • Deno supports both JavaScript and TypeScript out of the box.
  • Deno ships as a single executable with no dependencies.
  • Comes with built-in utilities such as a dependency inspector (deno info) and a code formatter (deno fmt).

Getting started#

deno.land/x is a hosting service for Deno scripts. It caches releases of open source modules stored on GitHub and serves them at one easy-to-remember domain. These modules contain small scripts that demonstrate use of Deno and its standard module.

The basic format of code URLs is

https://deno.land/x/IDENTIFIER@VERSION/FILE_PATH

Example#

https://deno.land/std@0.126.0/examples

In order to use Redis with Deno you will need a Deno Redis client. In the following sections, we will demonstrate the use of an experimental implementation of a Redis client for Deno.

Step 1. Set up a free Redis Cloud account#

Visit redis.com/try-free and create a free Redis Cloud account. Once you complete this tutorial, you will be provided with the database endpoint URL and password. Save it for future reference.

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Step 2. Get Deno#

brew install deno

Step 3. Verify if Deno is properly installed#

deno -V
deno 1.19.0

Step 4. Create an empty file with the following content#

The following code creates a connection to Redis using Deno:

import { connect } from 'https://deno.land/x/redis/mod.ts';
const redis = await connect({
  hostname: 'redis-18386.c110-qa.us-east-1-1.ec2.qa-cloud.redislabs.com',
  port: 18386,
  password: 'XXXX',
});
const ok = await redis.set('foo', 'bar');
const foo = await redis.get('foo');

Replace the values of hostname and port to match those of your Redis database, and add an extra password field if needed.

Step 5. Executing the script#

Deno can grab scripts from multiple sources. For example, you can provide a filename, a URL, or'-' to read the file from stdin. You can run a JavaScript or TypeScript program by executing deno run.

deno run --allow-net redis.ts

When you run the script, the value of foo should be output. You can verify this by running the monitor command:

redis-15692.c264.ap-south-1-1.ec2.cloud.redislabs.com:15692> monitor
OK
1646536310.435577 [0 122.171.165.94:50193] "AUTH" "(redacted)"
1646536310.475578 [0 122.171.165.94:50193] "SET" "foo" "bar"
1646536310.511578 [0 122.171.165.94:50193] "GET" "foo"

Additional references:#

Last updated on Feb 23, 2024