resolves #190: add historyMaxAge parameter (#191)

* resolves #190: add historyMaxAge parameter

* clean up type conversion

* fix comparison

Author: Fabilin

README.md

@@ -352,11 +352,12 @@ Objects implementing this interface can be passed to `renderChat` or to `TockCon
 
 #### `LocalStorageSettings`
 
-| Property name          | Type       | Description                                                                                                                                 |
-|------------------------|------------|---------------------------------------------------------------------------------------------------------------------------------------------|
-| `enableMessageHistory` | `boolean?` | If set to `true`, the most recent messages of a conversation will be persisted in the local storage. Defaults to `false`.                   |
-| `maxMessageCount`      | `number?`  | When message history is enabled, sets the max number of messages to store. Defaults to 10.                                                  |
-| `prefix`               | `string?`  | Prefix for local storage keys allowing communication with different bots from the same domain (used for both `userId` and message history). |
+| Property name          | Type       | Description                                                                                                                                                |
+|------------------------|------------|------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `enableMessageHistory` | `boolean?` | If set to `true`, the most recent messages of a conversation will be persisted in the local storage. Defaults to `false`.                                  |
+| `historyMaxAge`        | `number?`  | If set to a positive value, represents the number of seconds before the message history is cleared (the timeout is reset after each message received).     |
+| `maxMessageCount`      | `number?`  | When message history is enabled, sets the max number of messages to store. Defaults to 10.                                                                 |
+| `prefix`               | `string?`  | Prefix for local storage keys allowing communication with different bots from the same domain (used for both `userId` and message history).                |
 
 #### `NetworkSettings`
 

src/settings/TockSettings.tsx

@@ -6,6 +6,7 @@ export interface LocalStorageSettings {
   prefix: string;
   enableMessageHistory: boolean;
   maxMessageCount: number;
+  historyMaxAge: number;
 }
 
 export interface NetworkSettings {
@@ -28,6 +29,7 @@ export const defaultSettings: TockSettings = {
     prefix: '',
     enableMessageHistory: false,
     maxMessageCount: 10,
+    historyMaxAge: -1,
   },
   network: {
     disableSse: false,

src/useTock.ts

@@ -193,6 +193,10 @@ export const useTock0: (
         localStoragePrefix,
         'tockMessageHistory',
       );
+      const messageHistoryLastTime = retrievePrefixedLocalStorageKey(
+        localStoragePrefix,
+        'tockLastMessageTimestamp',
+      );
 
       const savedHistory = window.localStorage.getItem(messageHistoryLSKeyName);
       let history: Message[];
@@ -209,6 +213,7 @@ export const useTock0: (
         messageHistoryLSKeyName,
         JSON.stringify(history),
       );
+      window.localStorage.setItem(messageHistoryLastTime, '' + Date.now());
     },
     [localStoragePrefix, localStorageMaxMessages],
   );
@@ -668,13 +673,30 @@ export const useTock0: (
       localStoragePrefix,
       'tockHandledResponses',
     );
+    const messageHistoryLastTimeKey = retrievePrefixedLocalStorageKey(
+      localStoragePrefix,
+      'tockLastMessageTimestamp',
+    );
 
     const serializedHistory =
       storageAvailable('localStorage') && localStorageEnabled
         ? window.localStorage.getItem(messageHistoryLSKey)
         : undefined;
 
     if (serializedHistory) {
+      const historyMaxAge = localStorageSettings.historyMaxAge;
+      if (historyMaxAge > 0) {
+        const lastMessageTime = +(
+          window.localStorage.getItem(messageHistoryLastTimeKey) ?? 0
+        );
+        if ((Date.now() - lastMessageTime) / 1000 > historyMaxAge) {
+          window.localStorage.removeItem(messageHistoryLSKey);
+          window.localStorage.removeItem(quickReplyHistoryLSKey);
+          window.localStorage.removeItem(messageHistoryLastTimeKey);
+          return null;
+        }
+      }
+
       const messages = JSON.parse(serializedHistory);
       const quickReplies = JSON.parse(
         window.localStorage.getItem(quickReplyHistoryLSKey) || '[]',