Min Cost Climbing Stairs LeetCode solution in JavaScript

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var minCostClimbingStairs = function (cost) {
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  //this array will be populated with the minimum cost of each step starting from the top
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  let minCostArray = [];
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  //append a 0 at end to represent reaching the 'top'
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  minCostArray[cost.length] = 0;
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  //append the last stair to the end of the array
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  minCostArray[cost.length - 1] = cost[cost.length - 1];
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  //starts at -2 the length since we already have two elements in our array
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  for (let i = cost.length - 2; i > -1; i--) {
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    //checks which minimum cost is lower and assigns the value at that index accordingly
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    if (minCostArray[i + 1] < minCostArray[i + 2])
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      minCostArray[i] = cost[i] + minCostArray[i + 1];
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    else minCostArray[i] = cost[i] + minCostArray[i + 2];
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  }
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  //checks which of the first two options is the lowest cost
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  return minCostArray[0] > minCostArray[1] ? minCostArray[1] : minCostArray[0];
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};