Persistence

[vopamoi] / vopamoi.ts

diff --git a/vopamoi.ts b/vopamoi.ts
index 505781d70f5180513e5fa0f85616daee5bc0f549..4d6cd86bfe25289cca1a52969530f6e17851dfe2 100644 (file)
--- a/vopamoi.ts
+++ b/vopamoi.ts
@@ -1,3 +1,18 @@
+// Typescript doesn't know about MAX_SAFE_INTEGER??  This was supposed to be
+// fixed in typescript 2.0.1 in 2016, but is not working for me in typescript
+// 4.2.4 in 2022.  :( https://github.com/microsoft/TypeScript/issues/9937
+//const MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER;
+const MAX_SAFE_INTEGER = 9007199254740991;
+
+// A sane split that splits N *times*, leaving the last chunk unsplit.
+function splitN(str: string, delimiter: string, limit: number = MAX_SAFE_INTEGER): string[] {
+  if (limit < 1) {
+    return [str];
+  }
+  const at = str.indexOf(delimiter);
+  return at === -1 ? [str] : [str.substring(0, at)].concat(splitN(str.substring(at + delimiter.length), delimiter, limit - 1));
+}
+
 const Model = {
   createTask: function (description: string) {
     const task = document.createElement("div");
@@ -22,11 +37,41 @@ const Model = {
   },
 };
 
-const Log = {
-  addTask: function (description: string) {
-    Model.addTask(description);
-  },
-};
+const Log = (function () {
+  var next_log_index = 0;
+  return {
+    addTask: function (description: string) {
+      this.recordAndApplyLogEntry(`${Date.now()} Create ${description}`);
+    },
+
+    applyLogEntry: function (entry: string) {
+      const [timestamp, command, data] = splitN(entry, " ", 2);
+      if (command == "Create") {
+        Model.addTask(data);
+      }
+    },
+
+    recordLogEntry: function (entry: string) {
+      window.localStorage.setItem(`${next_log_index++}`, entry);
+    },
+
+    recordAndApplyLogEntry: function (entry: string) {
+      this.recordLogEntry(entry);
+      this.applyLogEntry(entry);
+    },
+
+    replay: function () {
+      while (true) {
+        const entry = window.localStorage.getItem(`${next_log_index}`);
+        if (entry === null) {
+          break;
+        }
+        this.applyLogEntry(entry);
+        next_log_index++;
+      }
+    },
+  };
+})();
 
 function handleKey(event: any) {
   if (event.target.tagName !== "INPUT") {
@@ -49,4 +94,5 @@ function browserCreateTask(form: any) {
 
 function browserInit() {
   document.body.addEventListener("keydown", handleKey, { capture: false });
+  Log.replay();
 }