Mini-mini-graph library for JS

graph.js

const create = () => {
  return { nodes: new Set(), edges: new Set() }
}

const addNode = (graph, node) => {
  graph.nodes.add(node)
}

const addEdge = (graph, [node1, node2]) => {
  if (graph.nodes.has(node1) && graph.nodes.has(node2)) {
    graph.edges.add([node1, node2])
  } else {
    throw new Error("You can't add an edge between nodes that aren't in the graph")
  }
}

const getConnected = (graph, node) => {
  const connected = new Set([node])
  graph.edges.forEach(([node1, node2]) => {
    if (node1 === node || node2 === node) {
      connected.add(node1 === node ? node2 : node1)
    }
  })
  return connected
}

const equalSets = (set, otherSet) => {
  if (set.size !== otherSet.size) return false
  for (let item of set) if (!otherSet.has(item)) return false
  return true
}

const recursiveGetConnected = (graph, node, connected = new Set(), visited = new Set()) => {
  connected.add(node)
  visited.add(node)
  getConnected(graph, node).forEach(nextNode => {
    if (!visited.has(nextNode)) {
      recursiveGetConnected(graph, nextNode, connected, visited)
    }
  })
  return connected
}

const cluster = graph => {
  const clusters = new Set()
  graph.nodes.forEach(n => clusters.add(recursiveGetConnected(graph, n)))
  const uniqClusters = []
  clusters.forEach(cluster1 => {
    if (uniqClusters.every(cluster2 => !equalSets(cluster1, cluster2))) {
      uniqClusters.push(cluster1)
    }
  })
  return new Set(uniqClusters)
}

const test = create()
addNode(test, "one")
addNode(test, "two")
addNode(test, "three")
addNode(test, "four")
addEdge(test, ["one", "two"])
addEdge(test, ["three", "one"])
console.log(cluster(test))