indentation issue

[Sec42]

I have stumbled upon the following issue with the javascript
indentation:

Let's assume that I have the following function with inconsistent indenting:

function hello(loc){
    console.log("hello",loc);
    if (loc == "world"){
      console.log("the whole world");
    }
    return true;
}

Now if I move the cursor to the "the whole world" line and press o to open a
new line, the cursor sits at column 9, not at column 7 where the
previous line started.

I have found that this seems to be, because at that point I had
shiftwidth set to 4.

The issue is, I'm editing code (written by someone else) that has
inconsistent indentation, so if I set "sw" to "2", it just breaks the
same way in other locations (this time for example with first
console.log line)

Is there a way to fix it so it honors the indentation of the current
block by default much like the builtin "C" indenting that vim has?