Greatest Sum Divisible by Three LeetCode solution in JavaScript

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var maxSumDivThree = function (nums) {
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  // there are 3 options for how the sum fit's into 3 via mod % 3
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  // track those 3 options via indices in the dp array
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  // dp[0] = %3 === 0
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  // dp[1] = %3 === 1
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  // dp[2] = %3 === 2
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  let dp = new Array(3).fill(0);
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  for (let num of nums) {
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    for (let i of dp.slice(0)) {
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      let sum = i + num;
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      let mod = sum % 3;
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      // on each pass, set the value of dp[mod] to the Math.max val
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      dp[mod] = Math.max(dp[mod], sum);
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    }
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  }
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  return dp[0];
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};