ES6 Default Function Parameters

Unlike the defining the default values in JavaScript, ES6 has provided a flexibility to define the default values during the function definition time.  In regular Javascript, we define a variable with one value, override that value with in the function logic. Here is an example to define default values in ES6.

function greet(name = ‘Student’, greeting = ‘Welcome’) {
return `${greeting} ${name}!`;

greet(); // Welcome Student!
greet(‘Mallik’); // Welcome Mallik!
greet(‘Mallik’, ‘Hi’); // Hi Mallik!

Output of above function:

Welcome Student!
Welcome Mallik!
Hi Mallik!

To create a default parameter, you add an equal sign ( = ) and then whatever you want the parameter to default to if an argument is not provided. In the above example, both parameters have default values of strings, but they can be any JavaScript type!