How to reverse array?-CodePudding

How to reverse array, or map with descending order?

<tbody>
  {Array(10).fill(1).map((el, i) =>
    <ObjectRow key={i} />
  )}
</tbody>

reverse function does not work

<tbody>
  {Array(10).fill(1).reverse().map((el, i) =>
    <ObjectRow key={i} />
  )}
</tbody>

CodePudding user response：

You have 2 mistakes here.

First you load an array with 1s, which means that you have identical elements inside your array, so reverse is pointless.

Second you use the index as a key inside your map method and not the actual reversed element (using index as key is not considered best practice).

The correct way should be

<tbody>
  { [...Array(10).keys()].reverse().map((el, i) =>
    <ObjectRow key={el} />
  )}
</tbody>