freeCodeCamp Intermediate Algorithm Scripting: Map the Debris

orbitalPeriod.js

// Return a new array that transforms the elements' average 
// altitude into their orbital periods (in seconds).
// The array will contain objects in the format {name: 'name', 
// avgAlt: avgAlt}.
// You can read about orbital periods on Wikipedia.
// The values should be rounded to the nearest whole number.
// The body being orbited is Earth.
// The radius of the earth is 6367.4447 kilometers, and the GM 
// value of earth is 398600.4418 km3s-2.

function orbitalPeriod(arr) {
  var GM = 398600.4418;
  var earthRadius = 6367.4447;
  return arr.map(satellite => {
    let alt=satellite.avgAlt;
    delete satellite.avgAlt;
    satellite["orbitalPeriod"] = Math.round(2 * Math.PI * Math.sqrt( Math.pow((alt+earthRadius),3) / GM));
    return satellite;
  });
}

orbitalPeriod([{name : "sputnik", avgAlt : 35873.5553}]); // [{name: "sputnik", orbitalPeriod: 86400}]
orbitalPeriod([{name: "iss", avgAlt: 413.6}, 
{name: "hubble", avgAlt: 556.7}, 
{name: "moon", avgAlt: 378632.553}]); // [{name : "iss", orbitalPeriod: 5557}, {name: "hubble", orbitalPeriod: 5734}, {name: "moon", orbitalPeriod: 2377399}].