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July 17, 2019 09:56
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| /*Intermediate Algorithm Scripting: Map the Debris | |
| 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. | |
| https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/intermediate-algorithm-scripting/map-the-debris*/ | |
| function orbitalPeriod(arr) { | |
| const GM = 398600.4418; //in km3s-2. | |
| const earthRadius = 6367.4447; //in km | |
| let resultArray = []; | |
| function findOrbitalPeriod(avgAlt){ | |
| //Using Kepler's Third Law, the orbital period T (in seconds), rounded, when given the AvgAlt of the body orbiting Earth. | |
| //See more on https://en.wikipedia.org/wiki/Orbital_period | |
| return Math.round(2 * Math.PI * Math.sqrt(Math.pow(earthRadius + avgAlt, 3) / GM)); | |
| } | |
| //https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map | |
| resultArray = arr.map(obj =>{ | |
| let rObj = {}; | |
| rObj.name = obj.name; | |
| rObj.orbitalPeriod = findOrbitalPeriod(obj.avgAlt) | |
| return rObj; | |
| }); | |
| return resultArray; | |
| } | |
| orbitalPeriod([{name : "sputnik", avgAlt : 35873.5553}]); | |
| /* | |
| orbitalPeriod([{name : "sputnik", avgAlt : 35873.5553}]) should return [{name: "sputnik", orbitalPeriod: 86400}]. | |
| Passed | |
| orbitalPeriod([{name: "iss", avgAlt: 413.6}, {name: "hubble", avgAlt: 556.7}, {name: "moon", avgAlt: 378632.553}]) should return [{name : "iss", orbitalPeriod: 5557}, {name: "hubble", orbitalPeriod: 5734}, {name: "moon", orbitalPeriod: 2377399}]. | |
| Passed | |
| */ |
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