what is opposite of split javascript code example

Example 1: javascript split by comma

<script>
var names = 'Harry,John,Clark,Peter,Rohn,Alice';
var nameArr = names.split(',');
console.log(nameArr);
 
// Accessing individual values
alert(nameArr[0]); // Outputs: Harry
alert(nameArr[1]); // Outputs: John
alert(nameArr[nameArr.length - 1]); // Outputs: Alice
 
var str = 'Hello World!';
var chars = str.split('');
console.log();
 
// Accessing individual values
alert(chars[0]); // Outputs: H
alert(chars[1]); // Outputs: e
alert(chars[chars.length - 1]); // Outputs: !
</script>

Example 2: javascript explode space

var str   = "my car is red";
var stringArray = str.split(/(\s+)/);

console.log(stringArray); // ["my", " ", "car", " ", "is", " ", "red"]