refactor to React Fiber

package/index.js

@@ -1,24 +1,28 @@
-const snapShot = [];
+const snapShot = { tree: null };
+
 const mode = { jumping: false };
 
-const linkState = require('./linkState')(snapShot, mode);
+const linkFiber = require('./linkFiber')(snapShot, mode);
 const timeJump = require('./timeJump')(snapShot, mode);
-const unlinkState = require('./unlinkState')(snapShot);
 
-const getShot = () => snapShot.map(({ component }) => component.state);
+const getTree = () => snapShot.tree.getCopy();
 
 window.addEventListener('message', ({ data: { action, payload } }) => {
-  console.log(action, payload);
-  if (action === 'jumpToSnap') {
-    timeJump(payload);
-  } else if (action === 'stepToSnap') {
-    payload.forEach(snap => timeJump(snap));
+  switch (action) {
+    case 'jumpToSnap':
+      timeJump(payload);
+      break;
+    case 'stepToSnap': {
+      const { steps, speed } = payload;
+      console.log('i would like to step through here');
+      break;
+    }
+    default:
   }
 });
 
 module.exports = {
-  linkState,
-  unlinkState,
   timeJump,
-  getShot,
+  linkFiber,
+  getTree,
 };

package/linkFiber.js

@@ -0,0 +1,72 @@
+// links component state tree to library
+// changes the setState method to also update our snapshot
+const Tree = require('./tree');
+
+module.exports = (snap, mode) => {
+  let fiberRoot = null;
+  let first = true;
+
+  function sendSnapshot() {
+    // don't send messages while jumping
+    if (mode.jumping) return;
+    const payload = snap.tree.getCopy();
+    window.postMessage({
+      action: 'recordSnap',
+      payload,
+    });
+  }
+
+  function changeSetState(component) {
+    // check that setState hasn't been changed yet
+    if (component.setState.name === 'newSetState') return;
+
+    // make a copy of setState
+    const oldSetState = component.setState.bind(component);
+
+    function newSetState(state, callback = () => { }) {
+      // continue normal setState functionality, except add sending message middleware
+      if (first) {
+        updateSnapShotTree();
+        sendSnapshot();
+        first = false;
+      }
+      oldSetState(state, () => {
+        updateSnapShotTree();
+        sendSnapshot();
+        callback();
+      });
+    }
+
+    // replace component's setState so developer doesn't change syntax
+    component.setState = newSetState;
+  }
+
+  function createTree(currentFiber, tree = new Tree('root')) {
+    if (!currentFiber) return tree;
+
+    const { sibling, stateNode, child } = currentFiber;
+
+    let nextTree = tree;
+    if (stateNode && stateNode.state) {
+      nextTree = tree.appendChild(stateNode);
+      changeSetState(stateNode);
+    }
+
+    // iterate through siblings
+    createTree(sibling, tree);
+    // iterate through children
+    createTree(child, nextTree);
+
+    return tree;
+  }
+
+  function updateSnapShotTree() {
+    const { current } = fiberRoot;
+    snap.tree = createTree(current);
+  }
+  return (container) => {
+    const { _reactRootContainer: { _internalRoot } } = container;
+    fiberRoot = _internalRoot;
+    updateSnapShotTree();
+  };
+};

package/timeJump.js

@@ -1,9 +1,31 @@
-module.exports = (snapShot, mode) => {
-  return (newSnapShot) => {
-    mode.jumping = true;
-    newSnapShot.forEach(async (state, i) => {
-      await snapShot[i].setStateAsync(state);
+// traverses given tree by accessing children through coords array
+function traverseTree(tree, coords) {
+  let curr = tree;
+  coords.forEach((coord) => {
+    curr = curr.children[coord];
+  });
+  return curr;
+}
+
+module.exports = (origin, mode) => {
+  // recursively change state of tree
+  function jump(target, coords = []) {
+    const originNode = traverseTree(origin.tree, coords);
+
+    // set the state of the origin tree
+    originNode.component.setState(target.component.state, () => {
+      // iterate through new children once state has been set
+      target.children.forEach((child, i) => {
+        jump(child, coords.concat(i));
+      });
     });
+  }
+
+
+  return (target) => {
+    // setting mode disables setState from posting messages to window
+    mode.jumping = true;
+    jump(target);
     mode.jumping = false;
   };
 };

package/tree.js

@@ -0,0 +1,43 @@
+class Tree {
+  constructor(component) {
+    // special case when component is root
+    // give it a special state = 'root'
+    // a setState function that just calls the callback instantly
+    this.component = (component === 'root') ? { state: 'root', setState: (partial, callback) => callback() } : component;
+    this.children = [];
+  }
+
+  appendChild(component) {
+    const child = new Tree(component);
+    this.children.push(child);
+    return child;
+  }
+
+  // deep copies only the state of each component and creates a new tree
+  getCopy(copy = new Tree(null)) {
+    const { state } = this.component;
+    if (!copy.component) copy.component = { state };
+
+    // copy state of children
+    copy.children = this.children.map(child => new Tree({ state: child.component.state }));
+
+    // copy children's children recursively
+    this.children.forEach((child, i) => child.getCopy(copy.children[i]));
+    return copy;
+  }
+
+  // print out the tree in the console
+  print() {
+    const children = ['children: '];
+    this.children.forEach((child) => {
+      children.push(child.component.state);
+    });
+    if (children.length === 1) console.log(this.component.state);
+    else console.log(this.component.state, ...children);
+    this.children.forEach((child) => {
+      child.print();
+    });
+  }
+}
+
+module.exports = Tree;