const elements = ['Sun', 'Earth', 'Moon'];
console.log(elements.join());
// output: "Sun,Earth,Moon"
console.log(elements.join(''));
// output: "SunEarthMoon"
console.log(elements.join('-'));
// output: "Sun-Earth-Moon"
const elements = ['Fire', 'Air', 'Water'];
console.log(elements.join());
// expected output: "Fire,Air,Water"
console.log(elements.join(''));
// expected output: "FireAirWater"
console.log(elements.join('-'));
// expected output: "Fire-Air-Water"var a = ['Wind', 'Water', 'Fire'];
a.join(); // 'Wind,Water,Fire'
a.join(', '); // 'Wind, Water, Fire'
a.join(' + '); // 'Wind + Water + Fire'
a.join(''); // 'WindWaterFire'