One line solution = ( [ TS, JS ] ) => Easy;
\nfunction findDifference(a: number[], b: number[]): number[][] {\n  return [[...new Set(a.filter(e=>!b.includes(e)))],[...new Set(b.filter(e =>!a.includes(e)))
```\nfunction findDifference(a: number[], b: number[]): number[][] {\n  return [[...new Set(a.filter(e=>!b.includes(e)))],[...new Set(b.filter(e =>!a.includes(e)))]];\n};\n```
['TypeScript', 'JavaScript']