One of the features added in ES6 is the ability to use default parameters. Default parameters allow parameters to have a predetermined value in case there is no argument passed into the function or if the argument is undefined
when called.
Take a look at the code snippet below that uses a default parameter:
- In the example above, we used the
=
operator to assign the parametername
a default value of'stranger'
. This is useful to have in case we ever want to include a non-personalized default greeting! - When the code calls
greeting('Nick')
the value of the argument is passed in and,'Nick'
, will override the default parameter of'stranger'
to log'Hello, Nick!'
to the console. - When there isn’t an argument passed into
greeting()
, the default value of'stranger'
is used, and'Hello, stranger!'
is logged to the console.
By using a default parameter, we account for situations when an argument isn’t passed into a function that is expecting an argument.