File: //home/arjun/projects/good-life-be/node_modules/uuid/README.md
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# uuid [](https://github.com/uuidjs/uuid/actions?query=workflow%3ACI) [](https://github.com/uuidjs/uuid/actions?query=workflow%3ABrowser)
For the creation of [RFC9562](https://www.rfc-editor.org/rfc/rfc9562.html) (formally [RFC4122](https://www.rfc-editor.org/rfc/rfc4122.html)) UUIDs
- **Complete** - Support for all RFC9562 (nee RFC4122) UUID versions
- **Cross-platform** - Support for ...
- CommonJS, [ECMAScript Modules](#ecmascript-modules) and [CDN builds](#cdn-builds)
- NodeJS 16+ ([LTS releases](https://github.com/nodejs/Release))
- Chrome, Safari, Firefox, Edge browsers
- Webpack and rollup.js module bundlers
- [React Native / Expo](#react-native--expo)
- **Secure** - Cryptographically-strong random values
- **Small** - Zero-dependency, small footprint, plays nice with "tree shaking" packagers
- **CLI** - Includes the [`uuid` command line](#command-line) utility
<!-- prettier-ignore -->
> [!NOTE]
> Upgrading from `uuid@3`? Your code is probably okay, but check out [Upgrading From `uuid@3`](#upgrading-from-uuid3) for details.
<!-- prettier-ignore -->
> [!NOTE]
> Only interested in creating a version 4 UUID? You might be able to use [`crypto.randomUUID()`](https://developer.mozilla.org/en-US/docs/Web/API/Crypto/randomUUID), eliminating the need to install this library.
## Quickstart
To create a random UUID...
**1. Install**
```shell
npm install uuid
```
**2. Create a UUID** (ES6 module syntax)
```javascript
import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'
```
... or using CommonJS syntax:
```javascript
const { v4: uuidv4 } = require('uuid');
uuidv4(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'
```
For timestamp UUIDs, namespace UUIDs, and other options read on ...
## API Summary
| | | |
| --- | --- | --- |
| [`uuid.NIL`](#uuidnil) | The nil UUID string (all zeros) | New in `uuid@8.3` |
| [`uuid.MAX`](#uuidmax) | The max UUID string (all ones) | New in `uuid@9.1` |
| [`uuid.parse()`](#uuidparsestr) | Convert UUID string to array of bytes | New in `uuid@8.3` |
| [`uuid.stringify()`](#uuidstringifyarr-offset) | Convert array of bytes to UUID string | New in `uuid@8.3` |
| [`uuid.v1()`](#uuidv1options-buffer-offset) | Create a version 1 (timestamp) UUID | |
| [`uuid.v1ToV6()`](#uuidv1tov6uuid) | Create a version 6 UUID from a version 1 UUID | New in `uuid@10` |
| [`uuid.v3()`](#uuidv3name-namespace-buffer-offset) | Create a version 3 (namespace w/ MD5) UUID | |
| [`uuid.v4()`](#uuidv4options-buffer-offset) | Create a version 4 (random) UUID | |
| [`uuid.v5()`](#uuidv5name-namespace-buffer-offset) | Create a version 5 (namespace w/ SHA-1) UUID | |
| [`uuid.v6()`](#uuidv6options-buffer-offset) | Create a version 6 (timestamp, reordered) UUID | New in `uuid@10` |
| [`uuid.v6ToV1()`](#uuidv6tov1uuid) | Create a version 1 UUID from a version 6 UUID | New in `uuid@10` |
| [`uuid.v7()`](#uuidv7options-buffer-offset) | Create a version 7 (Unix Epoch time-based) UUID | New in `uuid@10` |
| ~~[`uuid.v8()`](#uuidv8)~~ | "Intentionally left blank" | |
| [`uuid.validate()`](#uuidvalidatestr) | Test a string to see if it is a valid UUID | New in `uuid@8.3` |
| [`uuid.version()`](#uuidversionstr) | Detect RFC version of a UUID | New in `uuid@8.3` |
## API
### uuid.NIL
The nil UUID string (all zeros).
Example:
```javascript
import { NIL as NIL_UUID } from 'uuid';
NIL_UUID; // ⇨ '00000000-0000-0000-0000-000000000000'
```
### uuid.MAX
The max UUID string (all ones).
Example:
```javascript
import { MAX as MAX_UUID } from 'uuid';
MAX_UUID; // ⇨ 'ffffffff-ffff-ffff-ffff-ffffffffffff'
```
### uuid.parse(str)
Convert UUID string to array of bytes
| | |
| --------- | ---------------------------------------- |
| `str` | A valid UUID `String` |
| _returns_ | `Uint8Array[16]` |
| _throws_ | `TypeError` if `str` is not a valid UUID |
<!-- prettier-ignore -->
> [!NOTE]
> Ordering of values in the byte arrays used by `parse()` and `stringify()` follows the left ↠ right order of hex-pairs in UUID strings. As shown in the example below.
Example:
```javascript
import { parse as uuidParse } from 'uuid';
// Parse a UUID
const bytes = uuidParse('6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b');
// Convert to hex strings to show byte order (for documentation purposes)
[...bytes].map((v) => v.toString(16).padStart(2, '0')); // ⇨
// [
// '6e', 'c0', 'bd', '7f',
// '11', 'c0', '43', 'da',
// '97', '5e', '2a', '8a',
// 'd9', 'eb', 'ae', '0b'
// ]
```
### uuid.stringify(arr[, offset])
Convert array of bytes to UUID string
| | |
| -------------- | ---------------------------------------------------------------------------- |
| `arr` | `Array`-like collection of 16 values (starting from `offset`) between 0-255. |
| [`offset` = 0] | `Number` Starting index in the Array |
| _returns_ | `String` |
| _throws_ | `TypeError` if a valid UUID string cannot be generated |
<!-- prettier-ignore -->
> [!NOTE]
> Ordering of values in the byte arrays used by `parse()` and `stringify()` follows the left ↠ right order of hex-pairs in UUID strings. As shown in the example below.
Example:
```javascript
import { stringify as uuidStringify } from 'uuid';
const uuidBytes = [
0x6e, 0xc0, 0xbd, 0x7f, 0x11, 0xc0, 0x43, 0xda, 0x97, 0x5e, 0x2a, 0x8a, 0xd9, 0xeb, 0xae, 0x0b,
];
uuidStringify(uuidBytes); // ⇨ '6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b'
```
### uuid.v1([options[, buffer[, offset]]])
Create an RFC version 1 (timestamp) UUID
| | |
| --- | --- |
| [`options`] | `Object` with one or more of the following properties: |
| [`options.node` ] | RFC "node" field as an `Array[6]` of byte values (per 4.1.6) |
| [`options.clockseq`] | RFC "clock sequence" as a `Number` between 0 - 0x3fff |
| [`options.msecs`] | RFC "timestamp" field (`Number` of milliseconds, unix epoch) |
| [`options.nsecs`] | RFC "timestamp" field (`Number` of nanoseconds to add to `msecs`, should be 0-10,000) |
| [`options.random`] | `Array` of 16 random bytes (0-255) |
| [`options.rng`] | Alternative to `options.random`, a `Function` that returns an `Array` of 16 random bytes (0-255) |
| [`buffer`] | `Array \| Buffer` If specified, uuid will be written here in byte-form, starting at `offset` |
| [`offset` = 0] | `Number` Index to start writing UUID bytes in `buffer` |
| _returns_ | UUID `String` if no `buffer` is specified, otherwise returns `buffer` |
| _throws_ | `Error` if more than 10M UUIDs/sec are requested |
<!-- prettier-ignore -->
> [!NOTE]
> The default [node id](https://datatracker.ietf.org/doc/html/rfc9562#section-5.1) (the last 12 digits in the UUID) is generated once, randomly, on process startup, and then remains unchanged for the duration of the process.
<!-- prettier-ignore -->
> [!NOTE]
> `options.random` and `options.rng` are only meaningful on the very first call to `v1()`, where they may be passed to initialize the internal `node` and `clockseq` fields.
Example:
```javascript
import { v1 as uuidv1 } from 'uuid';
uuidv1(); // ⇨ '2c5ea4c0-4067-11e9-8bad-9b1deb4d3b7d'
```
Example using `options`:
```javascript
import { v1 as uuidv1 } from 'uuid';
const options = {
node: [0x01, 0x23, 0x45, 0x67, 0x89, 0xab],
clockseq: 0x1234,
msecs: new Date('2011-11-01').getTime(),
nsecs: 5678,
};
uuidv1(options); // ⇨ '710b962e-041c-11e1-9234-0123456789ab'
```
### uuid.v1ToV6(uuid)
Convert a UUID from version 1 to version 6
```javascript
import { v1ToV6 } from 'uuid';
v1ToV6('92f62d9e-22c4-11ef-97e9-325096b39f47'); // ⇨ '1ef22c49-2f62-6d9e-97e9-325096b39f47'
```
### uuid.v3(name, namespace[, buffer[, offset]])
Create an RFC version 3 (namespace w/ MD5) UUID
API is identical to `v5()`, but uses "v3" instead.
<!-- prettier-ignore -->
> [!IMPORTANT]
> Per the RFC, "_If backward compatibility is not an issue, SHA-1 [Version 5] is preferred_."
### uuid.v4([options[, buffer[, offset]]])
Create an RFC version 4 (random) UUID
| | |
| --- | --- |
| [`options`] | `Object` with one or more of the following properties: |
| [`options.random`] | `Array` of 16 random bytes (0-255) |
| [`options.rng`] | Alternative to `options.random`, a `Function` that returns an `Array` of 16 random bytes (0-255) |
| [`buffer`] | `Array \| Buffer` If specified, uuid will be written here in byte-form, starting at `offset` |
| [`offset` = 0] | `Number` Index to start writing UUID bytes in `buffer` |
| _returns_ | UUID `String` if no `buffer` is specified, otherwise returns `buffer` |
Example:
```javascript
import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'
```
Example using predefined `random` values:
```javascript
import { v4 as uuidv4 } from 'uuid';
const v4options = {
random: [
0x10, 0x91, 0x56, 0xbe, 0xc4, 0xfb, 0xc1, 0xea, 0x71, 0xb4, 0xef, 0xe1, 0x67, 0x1c, 0x58, 0x36,
],
};
uuidv4(v4options); // ⇨ '109156be-c4fb-41ea-b1b4-efe1671c5836'
```
### uuid.v5(name, namespace[, buffer[, offset]])
Create an RFC version 5 (namespace w/ SHA-1) UUID
| | |
| --- | --- |
| `name` | `String \| Array` |
| `namespace` | `String \| Array[16]` Namespace UUID |
| [`buffer`] | `Array \| Buffer` If specified, uuid will be written here in byte-form, starting at `offset` |
| [`offset` = 0] | `Number` Index to start writing UUID bytes in `buffer` |
| _returns_ | UUID `String` if no `buffer` is specified, otherwise returns `buffer` |
<!-- prettier-ignore -->
> [!NOTE]
> The RFC `DNS` and `URL` namespaces are available as `v5.DNS` and `v5.URL`.
Example with custom namespace:
```javascript
import { v5 as uuidv5 } from 'uuid';
// Define a custom namespace. Readers, create your own using something like
// https://www.uuidgenerator.net/
const MY_NAMESPACE = '1b671a64-40d5-491e-99b0-da01ff1f3341';
uuidv5('Hello, World!', MY_NAMESPACE); // ⇨ '630eb68f-e0fa-5ecc-887a-7c7a62614681'
```
Example with RFC `URL` namespace:
```javascript
import { v5 as uuidv5 } from 'uuid';
uuidv5('https://www.w3.org/', uuidv5.URL); // ⇨ 'c106a26a-21bb-5538-8bf2-57095d1976c1'
```
### uuid.v6([options[, buffer[, offset]]])
Create an RFC version 6 (timestamp, reordered) UUID
This method takes the same arguments as uuid.v1().
```javascript
import { v6 as uuidv6 } from 'uuid';
uuidv6(); // ⇨ '1e940672-c5ea-64c0-8bad-9b1deb4d3b7d'
```
Example using `options`:
```javascript
import { v6 as uuidv6 } from 'uuid';
const options = {
node: [0x01, 0x23, 0x45, 0x67, 0x89, 0xab],
clockseq: 0x1234,
msecs: new Date('2011-11-01').getTime(),
nsecs: 5678,
};
uuidv6(options); // ⇨ '1e1041c7-10b9-662e-9234-0123456789ab'
```
### uuid.v6ToV1(uuid)
Convert a UUID from version 6 to version 1
```javascript
import { v6ToV1 } from 'uuid';
v6ToV1('1ef22c49-2f62-6d9e-97e9-325096b39f47'); // ⇨ '92f62d9e-22c4-11ef-97e9-325096b39f47'
```
### uuid.v7([options[, buffer[, offset]]])
Create an RFC version 7 (random) UUID
| | |
| --- | --- |
| [`options`] | `Object` with one or more of the following properties: |
| [`options.msecs`] | RFC "timestamp" field (`Number` of milliseconds, unix epoch) |
| [`options.random`] | `Array` of 16 random bytes (0-255) |
| [`options.rng`] | Alternative to `options.random`, a `Function` that returns an `Array` of 16 random bytes (0-255) |
| [`options.seq`] | 31 bit monotonic sequence counter as `Number` between 0 - 0x7fffffff |
| [`buffer`] | `Array \| Buffer` If specified, uuid will be written here in byte-form, starting at `offset` |
| [`offset` = 0] | `Number` Index to start writing UUID bytes in `buffer` |
| _returns_ | UUID `String` if no `buffer` is specified, otherwise returns `buffer` |
Example:
```javascript
import { v7 as uuidv7 } from 'uuid';
uuidv7(); // ⇨ '01695553-c90c-722d-9b5d-b38dfbbd4bed'
```
### ~~uuid.v8()~~
**_"Intentionally left blank"_**
<!-- prettier-ignore -->
> [!NOTE]
> Version 8 (experimental) UUIDs are "[for experimental or vendor-specific use cases](https://www.rfc-editor.org/rfc/rfc9562.html#name-uuid-version-8)". The RFC does not define a creation algorithm for them, which is why this package does not offer a `v8()` method. The `validate()` and `version()` methods do work with such UUIDs, however.
### uuid.validate(str)
Test a string to see if it is a valid UUID
| | |
| --------- | --------------------------------------------------- |
| `str` | `String` to validate |
| _returns_ | `true` if string is a valid UUID, `false` otherwise |
Example:
```javascript
import { validate as uuidValidate } from 'uuid';
uuidValidate('not a UUID'); // ⇨ false
uuidValidate('6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b'); // ⇨ true
```
Using `validate` and `version` together it is possible to do per-version validation, e.g. validate for only v4 UUIds.
```javascript
import { version as uuidVersion } from 'uuid';
import { validate as uuidValidate } from 'uuid';
function uuidValidateV4(uuid) {
return uuidValidate(uuid) && uuidVersion(uuid) === 4;
}
const v1Uuid = 'd9428888-122b-11e1-b85c-61cd3cbb3210';
const v4Uuid = '109156be-c4fb-41ea-b1b4-efe1671c5836';
uuidValidateV4(v4Uuid); // ⇨ true
uuidValidateV4(v1Uuid); // ⇨ false
```
### uuid.version(str)
Detect RFC version of a UUID
| | |
| --------- | ---------------------------------------- |
| `str` | A valid UUID `String` |
| _returns_ | `Number` The RFC version of the UUID |
| _throws_ | `TypeError` if `str` is not a valid UUID |
Example:
```javascript
import { version as uuidVersion } from 'uuid';
uuidVersion('45637ec4-c85f-11ea-87d0-0242ac130003'); // ⇨ 1
uuidVersion('6ec0bd7f-11c0-43da-975e-2a8ad9ebae0b'); // ⇨ 4
```
<!-- prettier-ignore -->
> [!NOTE]
> This method returns `0` for the `NIL` UUID, and `15` for the `MAX` UUID.
## Command Line
UUIDs can be generated from the command line using `uuid`.
```shell
$ npx uuid
ddeb27fb-d9a0-4624-be4d-4615062daed4
```
The default is to generate version 4 UUIDS, however the other versions are supported. Type `uuid --help` for details:
```shell
$ npx uuid --help
Usage:
uuid
uuid v1
uuid v3 <name> <namespace uuid>
uuid v4
uuid v5 <name> <namespace uuid>
uuid v7
uuid --help
Note: <namespace uuid> may be "URL" or "DNS" to use the corresponding UUIDs
defined by RFC9562
```
## ECMAScript Modules
This library comes with [ECMAScript Modules](https://www.ecma-international.org/ecma-262/6.0/#sec-modules) (ESM) support for Node.js versions that support it ([example](./examples/node-esmodules/)) as well as bundlers like [rollup.js](https://rollupjs.org/guide/en/#tree-shaking) ([example](./examples/browser-rollup/)) and [webpack](https://webpack.js.org/guides/tree-shaking/) ([example](./examples/browser-webpack/)) (targeting both, Node.js and browser environments).
```javascript
import { v4 as uuidv4 } from 'uuid';
uuidv4(); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'
```
To run the examples you must first create a dist build of this library in the module root:
```shell
npm run build
```
## CDN Builds
### ECMAScript Modules
To load this module directly into modern browsers that [support loading ECMAScript Modules](https://caniuse.com/#feat=es6-module) you can make use of [jspm](https://jspm.org/):
```html
<script type="module">
import { v4 as uuidv4 } from 'https://jspm.dev/uuid';
console.log(uuidv4()); // ⇨ '1b9d6bcd-bbfd-4b2d-9b5d-ab8dfbbd4bed'
</script>
```
### UMD
As of `uuid@9` [UMD (Universal Module Definition)](https://github.com/umdjs/umd) builds are no longer shipped with this library.
If you need a UMD build of this library, use a bundler like Webpack or Rollup. Alternatively, refer to the documentation of [`uuid@8.3.2`](https://github.com/uuidjs/uuid/blob/v8.3.2/README.md#umd) which was the last version that shipped UMD builds.
## Known issues
### Duplicate UUIDs (Googlebot)
This module may generate duplicate UUIDs when run in clients with _deterministic_ random number generators, such as [Googlebot crawlers](https://developers.google.com/search/docs/advanced/crawling/overview-google-crawlers). This can cause problems for apps that expect client-generated UUIDs to always be unique. Developers should be prepared for this and have a strategy for dealing with possible collisions, such as:
- Check for duplicate UUIDs, fail gracefully
- Disable write operations for Googlebot clients
### "getRandomValues() not supported"
This error occurs in environments where the standard [`crypto.getRandomValues()`](https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues) API is not supported. This issue can be resolved by adding an appropriate polyfill:
### React Native / Expo
1. Install [`react-native-get-random-values`](https://github.com/LinusU/react-native-get-random-values#readme)
1. Import it _before_ `uuid`. Since `uuid` might also appear as a transitive dependency of some other imports it's safest to just import `react-native-get-random-values` as the very first thing in your entry point:
```javascript
import 'react-native-get-random-values';
import { v4 as uuidv4 } from 'uuid';
```
<!-- prettier-ignore -->
> [!NOTE]
> If you are using Expo, you must be using at least `react-native-get-random-values@1.5.0` and `expo@39.0.0`.
### Web Workers / Service Workers (Edge <= 18)
[In Edge <= 18, Web Crypto is not supported in Web Workers or Service Workers](https://caniuse.com/#feat=cryptography) and we are not aware of a polyfill (let us know if you find one, please).
### IE 11 (Internet Explorer)
Support for IE11 and other legacy browsers has been dropped as of `uuid@9`. If you need to support legacy browsers, you can always transpile the uuid module source yourself (e.g. using [Babel](https://babeljs.io/)).
## Upgrading From `uuid@7`
### Only Named Exports Supported When Using with Node.js ESM
`uuid@7` did not come with native ECMAScript Module (ESM) support for Node.js. Importing it in Node.js ESM consequently imported the CommonJS source with a default export. This library now comes with true Node.js ESM support and only provides named exports.
Instead of doing:
```javascript
import uuid from 'uuid';
uuid.v4();
```
you will now have to use the named exports:
```javascript
import { v4 as uuidv4 } from 'uuid';
uuidv4();
```
### Deep Requires No Longer Supported
Deep requires like `require('uuid/v4')` [which have been deprecated in `uuid@7`](#deep-requires-now-deprecated) are no longer supported.
## Upgrading From `uuid@3`
"_Wait... what happened to `uuid@4` thru `uuid@6`?!?_"
In order to avoid confusion with RFC [version 4](#uuidv4options-buffer-offset) and [version 5](#uuidv5name-namespace-buffer-offset) UUIDs, and a possible [version 6](http://gh.peabody.io/uuidv6/), releases 4 thru 6 of this module have been skipped.
### Deep Requires Now Deprecated
`uuid@3` encouraged the use of deep requires to minimize the bundle size of browser builds:
```javascript
const uuidv4 = require('uuid/v4'); // <== NOW DEPRECATED!
uuidv4();
```
As of `uuid@7` this library now provides ECMAScript modules builds, which allow packagers like Webpack and Rollup to do "tree-shaking" to remove dead code. Instead, use the `import` syntax:
```javascript
import { v4 as uuidv4 } from 'uuid';
uuidv4();
```
... or for CommonJS:
```javascript
const { v4: uuidv4 } = require('uuid');
uuidv4();
```
### Default Export Removed
`uuid@3` was exporting the Version 4 UUID method as a default export:
```javascript
const uuid = require('uuid'); // <== REMOVED!
```
This usage pattern was already discouraged in `uuid@3` and has been removed in `uuid@7`.
---
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