Deno Standard Library

High-quality APIs for Deno and the web. Use fearlessly.

Get Started

import { copy } from "https://deno.land/std@$STD_VERSION/fs/copy.ts";

await copy("./foo", "./bar");

See here for recommended usage patterns.

Documentation

Check out the documentation here.

Recommended Usage

1. Include the version of the library in the import specifier.

   Good:

   import { copy } from "https://deno.land/std@$STD_VERSION/fs/copy.ts";
   

2. Only import modules that you require.

   Bad (when using only one function):

   import * as fs from "https://deno.land/std@$STD_VERSION/fs/mod.ts";
   

   Good (when using only one function):

   import { copy } from "https://deno.land/std@$STD_VERSION/fs/copy.ts";
   

   Good (when using multiple functions):

   import * as fs from "https://deno.land/std@$STD_VERSION/fs/mod.ts";
   

3. Do not import symbols with an underscore in the name.

   Bad:

   import { _format } from "https://deno.land/std@$STD_VERSION/path/_common/format.ts";
   

4. Do not import modules with an underscore in the path.

   Bad:

   import { filterInPlace } from "https://deno.land/std@$STD_VERSION/collections/_utils.ts";
   

5. Do not import test modules or test data.

   Bad:

   import { test } from "https://deno.land/std@$STD_VERSION/front_matter/test.ts";
   

Stability

For background and discussions regarding the stability of the following
sub-modules, see #3489.

Design

Minimal Exports

Files are structured to minimize the number of dependencies they incur and the
amount of effort required to manage them, both for the maintainer and the user.
In most cases, only a single function or class, alongside its related types, are
exported. In other cases, functions that incur negligible dependency overhead
will be grouped together in the same file.

Deprecation Policy

We deprecate the APIs in the Standard Library when they get covered by new
JavaScript language APIs or new Web Standard APIs. These APIs are usually
removed after 3 minor versions.

If you still need to use such APIs after the removal for some reason (for
example, the usage in Fresh island), please use the URL pinned to the version
where they are still available.

For example, if you want to keep using readableStreamFromIterable, which was
deprecated and removed in favor of ReadableStream.from in v0.195.0, please
use the import URL pinned to v0.194.0:

import { readableStreamFromIterable } from "https://deno.land/std@0.194.0/streams/readable_stream_from_iterable.ts";

Contributing

Check out the contributing guidelines here.

Releases

The Standard Library is versioned independently of the Deno CLI. This will
change once the Standard Library is stabilized. See
here for the compatibility of different
versions of the Deno Standard Library and the Deno CLI.

A new minor version of the Standard Library is published at the same time as
every new version of the Deno CLI (including patch versions).

Badge

<a href="https://deno.land/std">
  <img
    width="135"
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    alt="Built with the Deno Standard Library"
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[![Built with the Deno Standard Library](https://raw.githubusercontent.com/denoland/deno_std/main/badge.svg)](https://deno.land/std)