feat: compare state equality

Author: oedotme

src/routers/createRouter.ts

@@ -1,6 +1,7 @@
 import { Signal, createSignal, onCleanup } from "solid-js";
 import type { LocationChange, RouterContext, RouterUtils } from "../types.ts";
 import { createRouterComponent } from "./components.jsx";
+import { equalObjects } from "../utils.js";
 
 function intercept<T>(
   [value, setValue]: [() => T, (v: T) => void],
@@ -32,7 +33,9 @@ export function createRouter(config: {
   let ignore = false;
   const wrap = (value: string | LocationChange) => (typeof value === "string" ? { value } : value);
   const signal = intercept<LocationChange>(
-    createSignal(wrap(config.get()), { equals: false }),
+    createSignal(wrap(config.get()), {
+      equals: (a, b) => a.value === b.value && equalObjects(a.state, b.state)
+    }),
     undefined,
     next => {
       !ignore && config.set(next);

src/routing.ts

@@ -44,7 +44,8 @@ import {
   joinPaths,
   scoreRoute,
   mergeSearchString,
-  expandOptionals
+  expandOptionals,
+  equalObjects
 } from "./utils.js";
 
 const MAX_REDIRECTS = 100;
@@ -327,26 +328,19 @@ export function createRouterContext(
   };
 
   createRenderEffect(() => {
-    const { value, state } = source();
+    const { value, state: nextState } = source();
     // Untrack this whole block so `start` doesn't cause Solid's Listener to be preserved
     untrack(() => {
-      if (value !== reference()) {
+      if (value !== reference() || !equalObjects(nextState, state())) {
         start(() => {
           intent = "native";
           setReference(value);
-          setState(state);
+          setState(nextState);
           resetErrorBoundaries();
           submissions[1]([]);
         }).then(() => {
           intent = undefined;
         });
-      } else {
-        start(() => {
-          intent = "native";
-          setState(state);
-        }).then(() => {
-          intent = undefined;
-        });
       }
     });
   });

src/utils.ts

@@ -186,3 +186,34 @@ export function expandOptionals(pattern: string): string[] {
     []
   );
 }
+
+// Modified from fast-deep-equal for objects only (MIT)
+// https://github.com/epoberezkin/fast-deep-equal
+export function equalObjects(a: any, b: any) {
+  if (a === b) return true;
+
+  if (a && b && typeof a == "object" && typeof b == "object") {
+    if (a.constructor !== b.constructor) return false;
+    if (a.valueOf !== Object.prototype.valueOf) return a.valueOf() === b.valueOf();
+    if (a.toString !== Object.prototype.toString) return a.toString() === b.toString();
+
+    var length, i, keys;
+    keys = Object.keys(a);
+    length = keys.length;
+
+    if (length !== Object.keys(b).length) return false;
+
+    for (i = length; i-- !== 0; ) {
+      if (!Object.prototype.hasOwnProperty.call(b, keys[i])) return false;
+    }
+
+    for (i = length; i-- !== 0; ) {
+      var key = keys[i];
+      if (!equalObjects(a[key], b[key])) return false;
+    }
+
+    return true;
+  }
+
+  return false;
+}