old_contents: // [0, 1, 2, 3, 4 ,5] => [[0, 1], [2, 3], [4, 5]]
  // (value: Array<any>, size: number) => Array<Array<any>>
  export default function unflatten(value, size) {
    const unflattened = []
  
    for (let i = 0; i < value.length; i += size) {
      const slice = value.slice(i, i + size)
      unflattened.push(slice)
    }
  
    return unflattened
  }
  
new_contents: // [0, 1, 2, 3, 4 ,5] => [[0, 1], [2, 3], [4, 5]]
  export default function unflatten(value, size) {
    const unflattened = []
  
    for (let i = 0; i < value.length; i += size) {
      const slice = value.slice(i, i + size)
      unflattened.push(slice)
    }
  
    return unflattened
  }
  
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