mirror of
https://github.com/denoland/deno.git
synced 2024-12-24 08:09:08 -05:00
73 lines
2.6 KiB
Markdown
73 lines
2.6 KiB
Markdown
# Introduction
|
|
|
|
Deno is a JavaScript/TypeScript runtime with secure defaults and a great
|
|
developer experience.
|
|
|
|
It's built on V8, Rust, and Tokio.
|
|
|
|
## Feature highlights
|
|
|
|
- Secure by default. No file, network, or environment access (unless explicitly
|
|
enabled).
|
|
- Supports TypeScript out of the box.
|
|
- Ships a single executable (`deno`).
|
|
- Has built-in utilities like a dependency inspector (`deno info`) and a code
|
|
formatter (`deno fmt`).
|
|
- Has
|
|
[a set of reviewed (audited) standard
|
|
modules](https://github.com/denoland/deno_std) that are guaranteed to work
|
|
with Deno.
|
|
- Can bundle scripts into a single JavaScript file.
|
|
|
|
## Philosophy
|
|
|
|
Deno aims to be a productive and secure scripting environment for the modern
|
|
programmer.
|
|
|
|
Deno will always be distributed as a single executable. Given a URL to a Deno
|
|
program, it is runnable with nothing more than
|
|
[the ~25 megabyte zipped executable](https://github.com/denoland/deno/releases).
|
|
Deno explicitly takes on the role of both runtime and package manager. It uses a
|
|
standard browser-compatible protocol for loading modules: URLs.
|
|
|
|
Among other things, Deno is a great replacement for utility scripts that may
|
|
have been historically written with Bash or Python.
|
|
|
|
## Goals
|
|
|
|
- Ship as just a single executable (`deno`).
|
|
- Provide secure defaults.
|
|
- Unless specifically allowed, scripts can't access files, the environment, or
|
|
the network.
|
|
- Be browser-compatible.
|
|
- The subset of Deno programs which are written completely in JavaScript and
|
|
do not use the global `Deno` namespace (or feature test for it), ought to
|
|
also be able to be run in a modern web browser without change.
|
|
- Provide built-in tooling to improve developer experience.
|
|
- E.g. unit testing, code formatting, and linting.
|
|
- Keep V8 concepts out of user land.
|
|
- Serve HTTP efficiently.
|
|
|
|
## Comparison to Node.js
|
|
|
|
- Deno does not use `npm`.
|
|
- It uses modules referenced as URLs or file paths.
|
|
- Deno does not use `package.json` in its module resolution algorithm.
|
|
- All async actions in Deno return a promise. Thus Deno provides different APIs
|
|
than Node.
|
|
- Deno requires explicit permissions for file, network, and environment access.
|
|
- Deno always dies on uncaught errors.
|
|
- Deno uses "ES Modules" and does not support `require()`. Third party modules
|
|
are imported via URLs:
|
|
|
|
```javascript
|
|
import * as log from "https://deno.land/std@$STD_VERSION/log/mod.ts";
|
|
```
|
|
|
|
## Other key behaviors
|
|
|
|
- Fetch and cache remote code upon first execution, and never update it until
|
|
the code is run with the `--reload` flag. (So, this will still work on an
|
|
airplane.)
|
|
- Modules/files loaded from remote URLs are intended to be immutable and
|
|
cacheable.
|