useProvideQueries
The useProvideQueries
hook is used to add a Queries
object by Id
to a Provider
component, but imperatively from a component within it.
useProvideQueries(
queriesId: string,
queries: Queries,
): void
Type | Description | |
---|---|---|
queriesId | string | The |
queries | Queries | The |
returns | void | This has no return value. |
Normally you will register a Queries
object by Id
in a context by using the queriesById
prop of the top-level Provider
component. This hook, however, lets you dynamically add a new Queries
object to the context, from within a component. This is useful for applications where the set of Queries
objects is not known at the time of the first render of the root Provider.
A Queries
object added to the Provider context in this way will be available to other components within the context (using the useQueries
hook and so on). If you use the same Id
as an existing Queries
object registration, the new one will take priority over one provided by the queriesById
prop.
Note that other components that consume a Queries
object registered like this should defend against it being undefined at first. On the first render, the other component will likely not yet have completed the registration. In the example below, we use the null-safe useQueries('petQueries')?
to do this.
Example
This example creates a Provider context. A child component registers a Queries
object into it which is then consumable by a peer child component.
import React from 'react';
import {createRoot} from 'react-dom/client';
import {createQueries, createStore} from 'tinybase';
import {
Provider,
useCreateQueries,
useCreateStore,
useProvideQueries,
useQueries,
} from 'tinybase/ui-react';
const App = () => (
<Provider>
<RegisterQueries />
<ConsumeQueries />
</Provider>
);
const RegisterQueries = () => {
const store = useCreateStore(() =>
createStore().setRow('pets', 'fido', {color: 'brown', legs: 4}),
);
const queries = useCreateQueries(store, (store) =>
createQueries(store).setQueryDefinition(
'brownLegs',
'pets',
({select, where}) => {
select('legs');
where('color', 'brown');
},
),
);
useProvideQueries('petQueries', queries);
return null;
};
const ConsumeQueries = () => (
<span>
{JSON.stringify(useQueries('petQueries')?.getResultTable('brownLegs'))}
</span>
);
const app = document.createElement('div');
const root = createRoot(app);
root.render(<App />);
console.log(app.innerHTML);
// -> '<span>{\"fido\":{\"legs\":4}}</span>'
Since
v5.3.0