base62

Base62.js

A JavaScript Base62 encode/decoder

What is Base62 encoding?

Base62 encoding converts numbers to ASCII strings (0-9, a-z and A-Z) and vice versa, which typically results in comparatively short strings. Such identifiers also tend to more readily identifiable by humans.

• 999 ≙ "g7"
• 9999 ≙ "2Bh"
• 238327 ≙ "ZZZ"

Installation

npm install base62

alternatively using Yarn:

yarn add base62

Usage

For backwards compatibility, Base62.js exposes v1.x's API by default – see Legacy API below. For efficiency, v2.x's modernized API allows selectively importing individual modules instead:

var base62 = require("base62/lib/ascii");

base62.encode(999);  // "g7"
base62.decode("g7"); // 999

This uses the default ASCII character set for encoding/decoding.

It's also possible to define a custom character set instead:

var base62 = require("base62/lib/custom");

var charset = "~9876543210ABCDEFGHIJKLMNOPQRSTU$#@%!abcdefghijklmnopqrstuvw-=";
charset = base62.indexCharset(charset);

base62.encode(999, charset);  // "F3"
base62.decode("F3", charset); // 999

Note that indexCharset typically expects the respective string to contain exactly 62 unique character, but does not validate this for efficieny. In fact, it's also possible to use characters sets with more than 62 characters in order to achieve shorter identifiers for large numbers.

Legacy API

Base62.js v1.x's API is maintained for backwards compatibility.

var base62 = require("base62");

base62.encode(999);  // "g7"
base62.decode("g7"); // 999

This uses the default ASCII character set for encoding/decoding.

It's also possible to define a custom character set instead:

var base62 = require("base62");

var charset = "~9876543210ABCDEFGHIJKLMNOPQRSTU$#@%!abcdefghijklmnopqrstuvw-=";
base62.setCharacterSet(charset);

base62.encode(999);  // "F3"
base62.decode("F3"); // 999

setCharacterSet ensures that the respective string contains exactly 62 unique characters.

Development

Source code is hosted on GitHub. Please report issues or feature requests in GitHub Issues.

Note on Patches/Pull Requests

• Fork the project.
• Make your feature addition or bug fix.
• Add tests for it. This is important so I don't break it in a future version unintentionally.
• Send me a pull request. Bonus points for topic branches.

Release Process for Maintainers

• Update the version number in package.json.
• Commit this change with the respective version number as commit message (e.g. "1.2.3").
• Create an annotated tag, using the prefixed version number (e.g. git tag -am "1.2.3" v1.2.3).
• Publish the new version: git push --tags origin master and npm publish.

Copyright

Copyright (c) 2016 Andrew Nesbitt. See LICENSE for details.

Similar packages

Other packages similar to base62

base-x

The base-x package is a versatile encoding library that supports custom base encoding schemes, including Base62. It is more flexible than base62 as it allows you to define your own character set for encoding and decoding.

base64url

The base64url package provides Base64 URL-safe encoding and decoding. While it focuses on Base64 rather than Base62, it is useful for similar applications where URL-safe encoding is required.

btoa

The btoa package provides Base64 encoding and decoding for Node.js. It is a simple and lightweight alternative for Base64 encoding, but does not support Base62.