Split into file-per-class

Collection.js

@@ -0,0 +1,54 @@
+class Collection {
+  constructor(nodes) {
+    this.nodes = nodes;
+  }
+
+  setTension() {
+    this.vec = [0, 0];
+    this.tension = 0;
+    for (let node of this.nodes) {
+      node.setTension();
+      for (let i of [0, 1]) {
+        this.vec[i] += node.vec[i];
+      };
+      this.tension += node.tension;
+    }
+  }
+
+  offsetCollides(graph, offset) {
+    // TODO: make this.nodes always a set
+    let nodeSet = new Set(this.nodes);
+    for (let node of this.nodes) {
+      let other = node.offsetCollides(graph, offset);
+      if (other && !nodeSet.has(other)) {
+        return other;
+      }
+    }
+    return null;
+  }
+
+  savePos() {
+    for (let node of this.nodes) {
+      node.savePos();
+    }
+  }
+
+  restorePos(graph) {
+    for (let node of this.nodes) {
+      node.restorePos(graph);
+    }
+  }
+
+  moveBy(graph, offset) {
+    let nodes = new Set(this.nodes);
+    while (nodes.size) {
+      for (let node of nodes) {
+        if (node.offsetCollides(graph, offset)) {
+          continue;
+        }
+        node.moveBy(graph, offset);
+        nodes.delete(node);
+      }
+    }
+  }
+}