Edit Distance LeetCode solution in JavaScript

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var minDistance = function (word1, word2) {
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  const m = word1.length;
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  const n = word2.length;
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  const memo = new Array(m).fill().map(() => new Array(n));
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  const dfs = (i = m - 1, j = n - 1) => {
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    if (i < 0 && j < 0) return 0;
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    if (i < 0 && j >= 0) return j + 1;
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    if (i >= 0 && j < 0) return i + 1;
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    if (memo[i][j] !== undefined) return memo[i][j];
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    if (word1[i] === word2[j]) {
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      return (memo[i][j] = dfs(i - 1, j - 1));
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    }
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    return (memo[i][j] =
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      1 + Math.min(...[dfs(i, j - 1), dfs(i - 1, j), dfs(i - 1, j - 1)]));
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  };
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  return dfs();
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};