Javascript implements elements in arrays to move up and down

Preface

We can move elements up and down when we swap arrays. We will use this effect in tables or previous sorting algorithms. Let’s take a look at an example of moving elements up and down in JavaScript to implement swap arrays in the upper and lower when we swap arrays.

When writing a project, you need to implement an example of an array recording moving up and down. It's not troublesome to write, it's nothing more than swapping array elements. The final implementation code is as follows, and the more important function is.

Sample code:

// Swap array elements  var swapItems = function(arr, index1, index2) {
    arr[index1] = (index2, 1, arr[index1])[0];
    return arr;
  };
 
  // Move up  $ = function(arr, $index) {
    if($index == 0) {
      return;
    }
    swapItems(arr, $index, $index - 1);
  };
 
  // Move down  $ = function(arr, $index) {
    if($index ==  -1) {
      return;
    }
    swapItems(arr, $index, $index + 1);
  };

Using that method reasonably can achieve some implementations of top and bottom.

Summarize

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