I'm trying to find the name of the practice (in any language) in which one checks for an object to be in existence before performing a lookup on it. Usually this is done by throwing in an `&&` in between the object and the object lookup expression, like so in JS:

```
var example = objectName && objectName.thing;

```

such that `example` is evaluated to either `undefined` or `objectName.thing`, and avoids a runtime error.

I could have sworn I've heard this before, but I've completely forgotten. What is this practice called?