Concatenation
Concatenation involves adding two or more strings together, creating a larger string containing the combined data of those original strings. The concatenation of a string appends one or more strings to another string. This is done in JavaScript using the following ways.
- using the  +operator
- using the concat()method
- using the array join()method
- using the template literal (introduced in ES6)
The string concat() method accepts the list of strings as parameters and returns a new string after concatenation i.e. combination of all the strings. Whereas the array join() method is used to concatenate all the elements present in an array by converting them into a single string. 
The template literal  uses backtick (``) and provides an easy way to create multiline strings and perform string interpolation. An expression can be used inside the backtick using $ sign and curly braces $(expression}.
const icon = '๐';
// using template Strings
`hi ${icon}`;
// using join() Method
['hi', icon].join(' ');
// using concat() Method
''.concat('hi ', icon);
//  using + operator
'hi ' + icon;
// hi ๐