JavaScript - OR Operation with two false values

Question

Related to coerce and default values in JavaScript, given this code:

function greet(name){
  name = name || '';
  console.log("Hello " + name);
}
greet();

Not given any name as parameter, we have

• undefined || ' '

And it's known that

• Boolean (undefined) coerces to false

• Boolean (' ') coerces to false

So we have:

false || false (undefined || ' ' )

Why the 'OR function' is returning the second parameter (' ') instead of the undefined if the undefined is first in the expression?