react-uid

Render-less container for ID generation

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react-uid
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UID

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To generate a stable UID/Key for a given 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 - <UID>{ id => <><label htmlFor={id}/><input id={id}/></>}</UID>
  • React Hooks - useUID

Javascript

  • uid(item, [index]) - generates UID for an object(array, function and so on), result could be used as React key. 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 ```js import {uid} from 'react-uid';

// objects const data = [{a:1}, {b:2}]; data.map( item =>

  • {item}
  • )

    // unique strings const data = ["a", "b"]; data.map( item =>

  • {item}
  • )

    // strings const data = ["a", "a"]; data.map( (item, index) => <li key={uid(item, index)}>{item})

    
    JS API might be NOT (multi-tenant)__SSR friendly__,
    
    #### React Components
    - (deprecated)`UID` - renderless container for generation Ids
    - `UIDConsumer` - renderless container for generation Ids
    ```js
     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 (16.8+)

    • useUID() will generate a "stable" UID
    • useUIDSeed() will generate a seed generator, you can use for multiple fields ```js import { useUID, useUIDSeed } from 'react-uid';

    const Form = () => { const uid = useUID();
    return ( <> Email: </> ) }

    const Form = () => { const seed = useUIDSeed();
    return ( <> <label htmlFor={seed('email')}>Email: <input id={seed('email')} name="email" /> {data.map(item =>

    ...
    </> ) }

    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 than `UID`, 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
    ```js
     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> 
             )}
         </UIDConsumer>
     </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

    If you find any bugs or have a feature request, please open an issue on github!

    The npm package download data comes from npm's download counts api and package details come from npms.io.