conacatenate elements of an array to a whole string code example
Example: .join in javascript
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"