useMetrics
The useMetrics hook is used to get a reference to a Metrics object from within a Provider component context.
useMetrics(id?: any): Metrics | undefined| Type | Description | |
|---|---|---|
id? | any | An optional |
| returns | Metrics | undefined | A reference to the |
A Provider component is used to wrap part of an application in a context. It can contain a default Metrics object (or a set of Metrics objects named by Id) that can be easily accessed without having to be passed down as props through every component.
The useMetrics hook lets you either get a reference to the default Metrics object (when called without a parameter), or one of the Metrics objects that are named by Id (when called with an Id parameter).
Examples
This example creates a Provider context into which a default Metrics object is provided. A component within it then uses the useMetrics hook to get a reference to the Metrics object again, without the need to have it passed as a prop.
const App = ({metrics}) => (
<Provider metrics={metrics}>
<Pane />
</Provider>
);
const Pane = () => <span>{useMetrics().getListenerStats().metric}</span>;
const metrics = createMetrics(createStore());
const app = document.createElement('div');
ReactDOMClient.createRoot(app).render(<App metrics={metrics} />);
console.log(app.innerHTML);
// -> '<span>0</span>'
This example creates a Provider context into which a Metrics object is provided, named by Id. A component within it then uses the useMetrics hook with that Id to get a reference to the Metrics object again, without the need to have it passed as a prop.
const App = ({metrics}) => (
<Provider metricsById={{petStore: metrics}}>
<Pane />
</Provider>
);
const Pane = () => (
<span>{useMetrics('petStore').getListenerStats().metric}</span>
);
const metrics = createMetrics(createStore());
const app = document.createElement('div');
ReactDOMClient.createRoot(app).render(<App metrics={metrics} />);
console.log(app.innerHTML);
// -> '<span>0</span>'