UID
To generate UID/Key for an item
, consistently between client and server, in 900 bytes.
Example - https://codesandbox.io/s/kkmwr6vv47
API
React UID provides 3 different APIs
- vanilla js API -
uid(item) -> key
- React Component, via renderProp based API - `{ id => <></>}
- React Hooks -
useUID
Javascript
uid(item, [index])
- generates UID for an object(array, function and so on), result could be used as Reactkey
.item
should be an object, but could be anything. In case it is not an "object", and might have non-unique value - you have to specify second argument -index
import {uid} from 'react-uid';
// objects
const data = [{a:1}, {b:2}];
data.map( item => <li key={uid(item)}>{item}</li>)
// unique strings
const data = ["a", "b"];
data.map( item => <li key={uid(item)}>{item}</li>)
// strings
const data = ["a", "a"];
data.map( (item, index) => <li key={uid(item, index)}>{item}</li>)
JS API might be NOT SSR friendly,
React Components
UID
- renderless container for generation Ids
import {UID} from 'react-uid';
<UID>
{id => (
<Fragment>
<input id={id} />
<label htmlFor={id} />
</Fragment>
)}
</UID>
// you can apply some "naming conventions" to the keys
<UID name={ id => `unique-${id}` }>
{id => (
<Fragment>
<input id={id} />
<label htmlFor={id} />
</Fragment>
)}
</UID>
// UID also provide `uid` as a second argument
<UID>
{(_, uid) => (
data.map( item => <li key={uid(item)}>{item}</li>)
)}
</UID>
// in the case `item` is not an object, but number or string - provide and index
<UID>
{(_, uid) => (
data.map( (item, index) => <li key={uid(item, index)}>{item}</li>)
)}
</UID>
The difference between uid
and UID
versions are in "nesting" - any UID
used inside another UID
would contain "parent prefix" in the result, scoping uid
to the local tree branch.
UID might be NOT SSR friendly,
Hooks (16.7+)
useUID()
will generate just a UIDuseUIDSeed()
will generate a seed generator, you can use for multiple fields
const Form = () => {
const uid = useUID();
return (
<>
<label for={uid}>Email: </label>
<input id={uid} name="email" />
</>
)
}
const Form = () => {
const seed = useUIDSeed();
return (
<>
<label for={seed('email')}>Email: </label>
<input id={seed('email')} name="email" />
{data.map(item => <div key={seed(item)}>...</div>
</>
)
}
Hooks API is SSR friendly,
Server-side friendly UID
UIDReset
,UIDConsumer
,UIDFork
- SSR friendly UID. Could maintain consistency across renders. They are much more complex thanUID
, and provide functionality you might not need.
The key difference - they are not using global "singlentone" to track used IDs, but read it from Context API, thus works without side effects.
Next example will generate the same code, regardless how many time you will render it
import {UIDReset, UIDConsumer} from 'react-uid';
<UIDReset>
<UIDConsumer>
{(id,uid) => (
<Fragment>
<input id={id} />
<label htmlFor={id} />
data.map( item => <li key={uid(item)}>{item}</li>)
</Fragment>
)}
</SmartUID>
</UIDReset>
UID is not 100% SSR friendly - use UIDConsumer.
Code splitting
Codesplitting may affect the order or existence of the components, so alter
the componentDidMount
order, and change the generated ID as result.
In case of SPA, this is not something you should be bothered about, but for SSR this could be fatal.
Next example will generate consistent keys regardless of component mount order.
Each call to UIDFork
creates a new branch of UIDs untangled from siblings.
import {UIDReset, UIDFork, UIDConsumer} from 'react-uid';
<UIDReset>
<UIDFork>
<AsyncLoadedCompoent>
<UIDConsumer>
{ uid => <span>{uid} is unique </span>}
</UIDConsumer>
</UIDFork>
<UIDFork>
<AsyncLoadedCompoent>
<UIDConsumer>
{ uid => <span>{uid} is unique </span>}
</UIDConsumer>
</UIDFork>
</UIDReset>
The hooks API only needs the <UIDFork>
wrapper.
So hard?
"Basic API" is not using Context API to keep realization simple, and React tree more flat.
Types
Written in TypeScript
Licence
MIT