Intl demo for Hermes

intl.cpp

// based on https://github.com/tmikov/hermes-jsi-demos/blob/master/hello/hello.cpp
// Intl calls from https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat

#include <hermes/hermes.h>
#include <iostream>

/// JS code to be executed.
static const char *code = R"(
  const date = new Date(Date.UTC(2020, 11, 20, 3, 23, 16, 738));
  print('Expected output: "12/20/2020"')
  print('Actual output:', new Intl.DateTimeFormat('en-US').format(date));

  print('Expected output: "20/12/2020"')
  print('Actual output:', new Intl.DateTimeFormat(['ban', 'id']).format(date));

  print('Expected output: "Sunday, 20 December 2020 at 14:23:16 GMT+11"')
  print(
    'Actual output:',
    new Intl.DateTimeFormat('en-GB', {
      dateStyle: 'full',
      timeStyle: 'long',
      timeZone: 'Australia/Sydney',
    }).format(date),
  );
)";

int main() {
  // You can Customize the runtime config here.
  auto runtimeConfig =
      hermes::vm::RuntimeConfig::Builder().withIntl(true).build();

  // Create the Hermes runtime.
  auto runtime = facebook::hermes::makeHermesRuntime(runtimeConfig);

  // Execute some JS.
  int status = 0;
  try {
    runtime->evaluateJavaScript(
        std::make_unique<facebook::jsi::StringBuffer>(code), "main.js");
  } catch (facebook::jsi::JSError &e) {
    // Handle JS exceptions here.
    std::cerr << "JS Exception: " << e.getStack() << std::endl;
    status = 1;
  } catch (facebook::jsi::JSIException &e) {
    // Handle JSI exceptions here.
    std::cerr << "JSI Exception: " << e.what() << std::endl;
    status = 1;
  }

  return status;
}

output.txt

Expected output: "12/20/2020"
Actual output: 1608434596738.000000
Expected output: "20/12/2020"
Actual output: 1608434596738.000000
Expected output: "Sunday, 20 December 2020 at 14:23:16 GMT+11"
Actual output: 1608434596738.000000