Question: Python's get method for dictionaries lets me specify what should be returned if a key doesn't exist. For my current case I want a dictionary returned. How do I do this in Javascript?

Answer: 
I prefer to use the logical OR like this:

```
foo.bar || 'default'

```

If checks is foo.bar is falsy, so it returns 'default' if bar is undefined.

You just need to care, that foo is an object. Otherwise a ReferenceError is thrown.
this works for me

```
let obj = {"a": 1};
let default = 100
obj["a"] || default; // -> 1
obj["b"] || default; // -> 100

```

But! there are some limitation, if `!!obj["a"] === false` we always get default value... so it's better to just check if key in obj, to be completely sure.