Utility for converting numbers to/from different bases/alphabets.

npm install bases
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Utility for converting numbers to/from different bases/alphabets. Common bases have convenience aliases (see below), but arbitrary/custom alphabets can be used.


npm install bases


var bases = require('./bases');

bases.toBase16(200);                // => 'c8'
bases.toBase62(99999);              // => 'q0T'
bases.toAlphabet(300, 'aAbBcC');    // => 'Abba'

bases.fromBase16('c8');               // => 200
bases.fromBase62('q0T');              // => 99999
bases.fromAlphabet('Abba', 'aAbBcC'); // => 300


Going from numbers to strings:

  • toAlphabet(num, alphabet): returns a string representation of the given number for the given alphabet, where the alphabet is an arbitrary string of characters. (See known alphabets below for examples.)

  • toBase(num, base): convenience helper for known bases (see below).

  • toBaseX(num): convenience helpers for known bases (see below), e.g. toBase62(num).

Going from strings to numbers:

  • fromAlphabet(str, alphabet): returns an integer representation of the given string for the given alphabet.

  • fromBase(num, base): convenience helper for known bases.

  • fromBaseX(str): convenience helpers for known bases.

Known Bases/Alphabets

  • Numbers: base-2 (01) through base-10 (0123456789).

  • Letters: base-26 (abcdefghijklmnopqrstuvwxyz, notice lowercase only) and base-52 (adds uppercase, i.e. abc...xyzABC...XYZ).

  • Numbers and letters: base-11 (base-10 + a) through base-16 (base-10 + abcdef), base-36 (base-10 + base-26) and base-62 (base-10 + base-52).

  • Human-friendly: base-32 as specified by Douglas Crockford (base-10 + uppercase base-26 - IOLU) and base-58 as specified by Flickr (base-62 - 0lIO).

  • Base-64 as standardized (ABC...XYZabc...xyz012...789+/). Besides there being many different standards, padding isn't currently added and line lengths aren't tracked. Not recommended for use with APIs that expect formal base-64 strings!


MIT license. (c) 2012-2014 Aseem Kishore and contributors.

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