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JavaScript JavaScript Foundations Functions Arguments

Posted by Michael Nickey
Michael Nickey
Courses Plus Student 13,524 Points

Default values for parameters

In this video you showed how to create a value inside the function to stop 'undefined' when a parameter is not used.

Can't we set a default value for the parameters when creating the function? Something like:

function addTheValues (a=0, b=0) {
    return a + b;
}

2 Answers

Andrew Kiernan
Andrew Kiernan
26,892 Points
Andrew Kiernan
Andrew Kiernan
26,892 Points

Hi Mike!

I believe there is a way you can set default values in a function. You can set each variable to the parameter value and use the or operater ( || ) to set a default value. So like this (the function will add the values you pass in, and would default to returning 4, for a=2, b=2): 

function addTheValues ( a, b ) {
  var a = a || 2;
  var b = b || 2;
  return a  + b
}
Michael Nickey
PLUS
Michael Nickey
Courses Plus Student 13,524 Points
Michael Nickey
Michael Nickey
Courses Plus Student 13,524 Points

Not quite what I was looking for but it'll work.

In Python we have something like this where we can define the variables inline as we note then between the parenthesis. 

>>> def F(a, b=[]):
...     b.append(a)
...     return b

Thanks though for the info.