Split classes out of Graph.js

GraphNode.js

@@ -0,0 +1,93 @@
+class GraphNode {
+  constructor() {
+    this.links = [];
+    this.linksIn = [];
+    this.groups = new Set();
+    this.affinity = [];
+    this.pageRank = 0;
+    this.subgraph = null;
+  }
+
+  incPageRank(visited) {
+    if (visited.has(this)) {
+      // Loop detection
+      return;
+    }
+    ++this.pageRank;
+    visited.add(this);
+    for (let to of this.links) {
+      to.incPageRank(visited);
+    }
+    visited.delete(this);
+  }
+
+  setSubgraph(subgraph, nodes) {
+    // Flood fill
+    if (this.subgraph !== null) {
+      return;
+    }
+    this.subgraph = subgraph;
+    nodes.delete(this);
+    for (let to of this.links) {
+      to.setSubgraph(subgraph, nodes);
+    }
+    for (let from of this.linksIn) {
+      from.setSubgraph(subgraph, nodes);
+    }
+    for (let group of this.groups.values()) {
+      for (let node of group.nodes) {
+        node.setSubgraph(subgraph, nodes);
+      }
+    }
+  }
+
+  setAffinity(nodes) {
+    const INF = 999999;
+    for (let node of nodes) {
+      // Weak affinity full mesh
+      // Keep unassociated subgroups together
+      this.addAffinity(node, d => d);
+
+      // Keep one space between subgraphs
+      if (this.subgraph != node.subgraph) {
+        this.addAffinity(node, d => d < 1.5 ? -INF : 0);
+      }
+
+      // Keep one space around groups
+      if (this.groups.size && !intersects(this.groups, node.groups)) {
+        node.addAffinity(this, d => d < 1.5 ? -INF : 0);
+      }
+    }
+    for (let to of this.links) {
+      // Stronger affinity for links
+      // Prefer to move toward the target instance
+      this.addAffinity(to, d => d < 1.5 ? -INF : d * 11);
+      to.addAffinity(this, d => d < 1.5 ? -INF : d * 9);
+    }
+    for (let group of this.groups.values()) {
+      for (let node of group.nodes) {
+        this.addAffinity(node, d => d * 100);
+      }
+    }
+  }
+
+  addAffinity(node, distanceToWeight) {
+    if (this == node) {
+      return;
+    }
+    this.affinity.push({
+      node: node,
+      distanceToWeight: distanceToWeight,
+    });
+  }
+
+  static process(item, soft=false) {
+    if (item.label == '') {
+      return null;
+    }
+    let node = new GraphNode();
+    node.label = item.label;
+    node.soft = soft;
+    return node;
+  }
+}