`useCheckpointsOrCheckpointsById`

The useCheckpointsOrCheckpointsById hook is used to get a reference to a Checkpoints object from within a Provider component context, or have it passed directly to this hook.

useCheckpointsOrCheckpointsById(checkpointsOrCheckpointsId?: CheckpointsOrCheckpointsId): Checkpoints | undefined

Type Description

	Type	Description
`checkpointsOrCheckpointsId?`	`CheckpointsOrCheckpointsId`	Either an `Id` for accessing a `Checkpoints` object that was named with an `Id` in the Provider, or the `Checkpoints` object itself.
returns	`Checkpoints \| undefined`	A reference to the `Checkpoints` object (or `undefined` if not within a Provider context, or if the requested `Checkpoints` object does not exist).

checkpointsOrCheckpointsId?

CheckpointsOrCheckpointsId

Either an Id for accessing a Checkpoints object that was named with an Id in the Provider, or the Checkpoints object itself.

returns

Checkpoints | undefined

A reference to the Checkpoints object (or undefined if not within a Provider context, or if the requested Checkpoints object does not exist).

This is mostly of use when you are developing a component that needs a Checkpoints object and which might have been passed in explicitly to the component or is to be picked up from the context by Id (a common pattern for Checkpoints-based components).

This is unlikely to be used often. For most situations, you will want to use the useCheckpoints hook.

Example

This example creates a Provider context into which a default Checkpoints object is provided. A component within it then uses the useCheckpointsOrCheckpointsById hook to get a reference to the Checkpoints object again, without the need to have it passed as a prop. Note however, that unlike the useCheckpoints hook example, this component would also work if you were to pass the Checkpoints object directly into it, making it more portable.

import React from 'react';
import {createRoot} from 'react-dom/client';
import {createCheckpoints, createStore} from 'tinybase';
import {
  Provider,
  useCheckpointsOrCheckpointsById,
} from 'tinybase/ui-react';

const App = ({checkpoints}) => (
  <Provider checkpoints={checkpoints}>
    <Pane />
  </Provider>
);
const Pane = ({checkpoints}) => (
  <span>
    {JSON.stringify(
      useCheckpointsOrCheckpointsById(checkpoints).getCheckpointIds(),
    )}
  </span>
);

const checkpoints = createCheckpoints(createStore());
const app = document.createElement('div');
const root = createRoot(app);
root.render(<App checkpoints={checkpoints} />);
console.log(app.innerHTML);
// -> '<span>[[],"0",[]]</span>'

Since

v4.1.0