# Early exits

```javascript
function transformData(rawData) {
  // check if no data
  if (!rawData) {
    return [];
  }

  // check for specific case
  if (rawData.length == 1) {
    return [];
  }

  // actual function code goes here
  return rawData.map((item) => item);
}
```

* encourages thinking around invalid/edge cases and how those cases should be handled
* avoids accidental and unnecessary processing of code against an unexpected use case
* mentally allows me to process each use case much more clearly
* once adopted, you can quickly glance at functions and understand the flow and execution which typically follows a top down approach going from - invalid cases -> small cases -> expected case