A context with a working default in React
React interview exercise on Context & reducers, difficulty 2 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Export CurrencyContext with the default { locale: "en-US", currency: "USD" }, and Price({ amount }) rendering <span className="price"> with the amount formatted by Intl.NumberFormat as currency for the context's locale and currency.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.