Frog Jump LeetCode solution in JavaScript

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var canCross = function (stones) {
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  let hash = {};
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  function dfs(idx = 0, jumpUnits = 0) {
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    let key = `${idx}-${jumpUnits}`;
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    if (key in hash) return hash[key];
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    if (idx === stones.length - 1) return true;
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    if (idx >= stones.length) return false;
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    let minJump = jumpUnits - 1,
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      maxJump = jumpUnits + 1;
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    for (let i = idx + 1; i < stones.length; i++) {
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      let jump = stones[i] - stones[idx];
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      if (jump >= minJump && jump <= maxJump) {
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        if (dfs(i, jump)) return (hash[idx] = true);
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      } else if (jump > maxJump) break;
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    }
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    return (hash[key] = false);
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  }
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  return dfs();
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};