uid-generator
v2.0.0
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Generates cryptographically strong pseudo-random UIDs with custom size and base-encoding
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uid-generator
Generates cryptographically strong, pseudo-random UIDs with custom size and base-encoding. Generated UIDs are strings that are guaranteed to always be the same length depending on the specified bit-size.
Great for generating things like compact API keys and UIDs that are safe to use in URLs and cookies.
Tip: The main benefit of this module is the ability to easily generate human-safe UIDs (using base58) and large UIDs that are more compact (using something like base94). If you’re just looking to generate URL-safe base64 IDs, the best package for that is uid-safe
.
Installation
npm install uid-generator --save
# or
yarn add uid-generator
Usage
const UIDGenerator = require('uid-generator');
const uidgen = new UIDGenerator(); // Default is a 128-bit UID encoded in base58
// Async with `await`
await uidgen.generate(); // -> 'B1q2hUEKmeVp9zWepx9cnp'
// Async with promise
uidgen.generate()
.then(uid => console.log(uid)); // -> 'PXmRJVrtzFAHsxjs7voD5R'
// Async with callback
uidgen.generate((err, uid) => {
if (err) throw err;
console.log(uid); // -> '4QhmRwHwwrgFqXULXNtx4d'
});
// Sync
uidgen.generateSync(); // -> '8Vw3bgbMMzeYfrQHQ8p3Jr'
API
new UIDGenerator([bitSize][, baseEncoding])
Creates a new UIDGenerator
instance that generates bitSize
-bit or uidLength
-sized UIDs encoded using the characters in baseEncoding
.
| Param | Type | Default | Description
|----------------|--------- |-----------------------|-------------
| [bitSize] | number
| 128
| The size of the UID to generate in bits. Must be a multiple of 8
.
| [baseEncoding] | string
| UIDGenerator.BASE58
| One of the UIDGenerator.BASE##
constants or a custom string of characters to use to encode the UID.
Note: If a custom baseEncoding
that has URL-unsafe characters is used, it is up to you to URL-encode the resulting UID.
Example
new UIDGenerator();
new UIDGenerator(256);
new UIDGenerator(UIDGenerator.BASE16);
new UIDGenerator(512, UIDGenerator.BASE62);
new UIDGenerator('01'); // Custom encoding (base2)
uidgen.generate([cb]) ⇒ ?Promise<string>
Asynchronously generates a UID.
| Param | Type | Description |
|-------|------|-------------|
| [cb] | ?function(error, uid)
| An optional callback that will be called with the results of generating the UID.If not specified, the function will return a promise. |
Returns: ?Promise<string>
- A promise that will resolve with the UID or reject with an error. Returns nothing if the cb
parameter is specified.
async
/await
Example
const uidgen = new UIDGenerator();
// This must be inside an async function
const uid = await uidgen.generate();
Promise Example
const uidgen = new UIDGenerator();
uidgen.generate()
.then(uid => {
// Use uid here
});
Callback Example
const uidgen = new UIDGenerator();
uidgen.generate((err, uid) => {
if (err) throw err;
// Use uid here
});
uidgen.generateSync() ⇒ string
Synchronously generates a UID.
Returns: string
- The generated UID.
Example
const uidgen = new UIDGenerator();
const uid = uidgen.generateSync();
(readonly) uidgen.bitSize : number
The size of the UID that will be generated in bits (the bitSize
value passed to the UIDGenerator
constructor).
If the uidLength
parameter is passed to the constructor instead of bitSize
, bitSize
is calculated as follows:
bitSize = Math.ceil(length * Math.log2(base));
Example
new UIDGenerator().bitSize // -> 128
new UIDGenerator(256).bitSize // -> 256
(readonly) uidgen.uidLength : number
The length of the UID string that will be generated. The generated UID will always be this length.
This will be the same as the uidLength
parameter passed to the UIDGenerator
constructor.
If the uidLength
parameter is not passed to the constructor, it will be calculated using the bitSize
parameter as follows:
uidLength = Math.ceil(bitSize / Math.log2(base))
Example
new UIDGenerator().uidLength // -> 22
new UIDGenerator(256, UIDGenerator.BASE62).uidLength // -> 43
(readonly) uidgen.baseEncoding : string
The set of characters used to encode the UID string (the baseEncoding
value passed to the UIDGenerator
constructor).
Example
new UIDGenerator().baseEncoding // -> '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
new UIDGenerator(UIDGenerator.BASE16).baseEncoding // -> '0123456789abcdef'
new UIDGenerator('01').baseEncoding // -> '01'
(readonly) uidgen.base : number
The base of the UID that will be generated (which is the number of characters in the baseEncoding
).
Example
new UIDGenerator().base // -> 58
new UIDGenerator(UIDGenerator.BASE16).base // -> 16
new UIDGenerator('01').base // -> 2
UIDGenerator.BASE16 : string
0123456789abcdef
UIDGenerator.BASE36 : string
0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ
UIDGenerator.BASE58 : string
123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz
(all alphanumeric characters except for 0
, O
, I
, and l
— characters easily mistaken for each other)
The default base.
Tip: Use this base to create UIDs that are easy to type in manually.
UIDGenerator.BASE62 : string
0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
UIDGenerator.BASE66 : string
0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-._~
(all ASCII characters that do not need to be encoded in a URI as specified by RFC 3986)
UIDGenerator.BASE71 : string
0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!'()*-._~
(all ASCII characters that are not encoded by encodeURIComponent()
)
UIDGenerator.BASE94 : string
!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
(all readable ASCII characters)