How TO - Set Default Parameters
Learn how to set default parameter values for JavaScript functions.
Default Parameters
If a function in JavaScript is called with missing arguments (less than declared), the missing values are set to
undefined.
Sometimes this is acceptable, but sometimes it is better to assign a default value to the parameter:
ECMAScript 2015 allows default parameter values in the function declaration:
function (x, y = 2) {
// function code
}
Try it Yourself »
Read more about functions in our JavaScript Function Tutorial.
