1var colors = ["red", "blue", "green"];
2var colorsCSV = colors.join(","); //"red,blue,green"

1[1, 2, 3].join(""); // 123
2

1[1, 2, 3].join(""); // 123

1let numbers = [0, 1, 2, 3];
2let numbersToString = numbers.toString();
3
4console.log(numbersToString);
5// output is "0,1,2,3"