React Context Example 1

currency-context.js

import * as React from "react";

const Ctx = React.createContext({
  currency: "USD",
  format: (val) => val,
  setCurrency: () => {},
});

Ctx.displayName = "CurrencyCtx";

function CurrencyProvider(props) {
  const [currency, setCurrency] = React.useState("USD");
  const format = React.useCallback(
    (value) => {
      return `${value} ${currency}`;
    },
    [currency]
  );
  return (
    <Ctx.Provider value={{ currency, format, setCurrency }} {...props} />
  );
}

const useCurrency = () => React.useContext(Ctx);

export { CurrencyProvider, useCurrency };