Number of People Aware of a Secret LeetCode solution in JavaScript

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/**
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 * @param {number} n
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 * @param {number} delay
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 * @param {number} forget
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 * @return {number}
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 */
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var peopleAwareOfSecret = function (n, delay, forget) {
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  const dp = new Array(n + 1).fill(0);
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  let numberOfPeopleSharingSecret = 0;
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  let totalNumberOfPeopleWithSecret = 0;
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  const MOD = 1000000007n;
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  dp[1] = 1; // as on day one only one person knows the secret
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  for (let i = 2; i <= n; i++) {
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    const numberOfNewPeopleSharingSecret = dp[Math.max(i - delay, 0)];
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    const numberOfPeopleForgettingSecret = dp[Math.max(i - forget, 0)];
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    numberOfPeopleSharingSecret =
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      BigInt(numberOfPeopleSharingSecret) +
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      ((BigInt(numberOfNewPeopleSharingSecret) -
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        BigInt(numberOfPeopleForgettingSecret) +
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        BigInt(MOD)) %
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        BigInt(MOD));
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    dp[i] = numberOfPeopleSharingSecret;
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  }
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  for (let i = n - forget + 1; i <= n; i++) {
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    totalNumberOfPeopleWithSecret =
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      (BigInt(totalNumberOfPeopleWithSecret) + BigInt(dp[i])) % BigInt(MOD);
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  }
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  return totalNumberOfPeopleWithSecret;
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};