feat: add delAll method (#2)

* feat: add delAll method

* fix: add delAll documentation, upgrade wording

* fix: correct delAll documentation

Co-authored-by: Dali Dosso-Dautais <dali@hicsuntdev.com>

README.md

@@ -76,6 +76,14 @@ cache.del(key)
 ```javascript
 await cache.del(`userInfo:${userId}`);
 ```
+### delAll
+```javascript
+cache.delAll(match, count)
+```
+ Return a Promise.
+```javascript
+await cache.delAll('userInfo:*', 100);
+```
 ### set: 
 ```javascript
 cache.set(key, value)
@@ -118,4 +126,8 @@ console.log(userInfo);
 
 // If the user is Updated, you can del or set the key to invalide the cache and requesting a new fetch on the next req.
 await cache.del(`userInfo:${userId}`);
-```
+
+// If there are multiple users, you can delete all this keys
+await cache.delAll('userInfo:*', 100);
+```
+

index.js

@@ -104,6 +104,39 @@ class Cache {
       return true;
     });
   }
+
+  delAll(match, count = 100) {
+    return new Promise((resolve, reject) => {
+      const timeout = setTimeout(() => {
+        reject(new Error('Timeout has occurred in delAll'))
+      }, 10000);
+      const promises = [];
+      const stream = this.cache.scanStream({ count, match });
+      let pipeline = this.cache.pipeline();
+      let nbWaiting = 0;
+      stream.on('data', (keys) => {
+        keys.forEach((key) => {
+          pipeline.del(key);
+        });
+        nbWaiting += keys.length;
+        if (nbWaiting > count) {
+          promises.push(new Promise(resolve => pipeline.exec(resolve)));
+          nbWaiting = 0;
+          pipeline = this.cache.pipeline();
+        }
+      });
+      stream.on('end', async () => {
+        promises.push(new Promise(resolve => pipeline.exec(resolve)));
+        await Promise.all(promises);
+        clearTimeout(timeout);
+        resolve();
+      });
+      stream.on('error', (error) => {
+        clearTimeout(timeout);
+        reject(error);
+      });
+    });
+  }
 
   flush() {
     this.cache.flushall('ASYNC');