Critical Connections in a Network LeetCode solution in JavaScript

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var criticalConnections = function (n, connections) {
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  // Graph Formation
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  const graph = new Map();
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  connections.forEach(([a, b]) => {
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    const aconn = graph.get(a) || [];
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    const bconn = graph.get(b) || [];
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    aconn.push(b), bconn.push(a);
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    graph.set(a, aconn);
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    graph.set(b, bconn);
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  });
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  // Find Bridges
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  const bridges = [];
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  const visited = new Array(n).fill(false);
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  const tin = new Array(n).fill(-1);
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  const dis = new Array(n).fill(-1);
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  let time = 0;
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  const dfs = (node, parent = -1) => {
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    visited[node] = true;
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    ++time;
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    tin[node] = time;
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    dis[node] = time;
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    const connections = graph.get(node);
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    for (let conn of connections) {
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      if (conn == parent) {
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        continue;
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      }
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      if (visited[conn]) {
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        dis[node] = Math.min(dis[node], tin[conn]);
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      } else {
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        dfs(conn, node);
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        dis[node] = Math.min(dis[node], dis[conn]);
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        if (dis[conn] > tin[node]) {
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          bridges.push([node, conn]);
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        }
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      }
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    }
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  };
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  dfs(0);
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  return bridges;
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};