1313. Decompress Run-Length Encoded List

We are given a list nums of integers representing a list compressed with run-length encoding.
Consider each adjacent pair of elements [freq, val] = [nums[2i], nums[2i+1]] (with i >= 0). For each such pair, there are freq elements with value val concatenated in a sublist. Concatenate all the sublists from left to right to generate the decompressed list.
Return the decompressed list.

• Example 1:
  Input: nums = [1,2,3,4]
  Output: [2,4,4,4]
  Explanation: The first pair [1,2] means we have freq = 1 and val = 2 so we generate the array [2].
  The second pair [3,4] means we have freq = 3 and val = 4 so we generate [4,4,4].
  At the end the concatenation [2] + [4,4,4] is [2,4,4,4].

• Example 2:
  Input: nums = [1,1,2,3]
  Output: [1,3,3]

var decompressRLElist = function(nums) {
    let group = [];
    while(nums.length !== 0) {
      group.push(nums.splice(0, 2))
    }
    let result = [];
    for(let i=0; i < group.length; i++) {
      let value = group[i][1];
      let times = group[i][0];
      while(times > 0) {
        result.push(value);
        times--
      }
    }
    return result
};