function validNumber(...anyAmountOfArgs) {
    return anyAmountOfArgs.every((val) => Number.isFinite(val) && val > 0);
}

// Validate distance and duration always
// using 2 params
if (!validNumber(distance, duration)) {
  alert("Please enter positive numbers for distance and duration.");
  return;
}

// Validate cadence if running
// using 1 param
if (type === "running" && !validNumber(cadence)) {
  alert("Please enter a positive number for cadence.");
  return;
}

import React from "react";
import ReactDOM from "react-dom";

class App extends React.Component {
  render() {
    return [
      {
        name: "Sam",
        email: "somewhere@gmail.com",
        public: false
      },

      {
        name: "Ash",
        email: "something@gmail.com",
        public: true
      }
    ].map((anObjectMapped, index) => {
      return anObjectMapped.public ? (
        <p key={`${anObjectMapped.name}_{anObjectMapped.email}`}>
          {anObjectMapped.name} - {anObjectMapped.email}
        </p>
      ) : null;
    });
  }
}

ReactDOM.render(<App />, document.getElementById("container"));