Version 2.0

classes/caching/file_system_cache.js

@@ -0,0 +1,29 @@
+const FPersist = require('fpersist');
+const KeyTimeout = require('./key_timeout.js');
+
+module.exports = class FileSystemCache {
+  constructor(options = {}) {
+    this.ttl = options.ttl;
+    this.keyTimeout = new KeyTimeout();
+
+    const cacheDirectory = options.cacheDirectory || '.cache';
+    this.cache = new FPersist(cacheDirectory);
+  }
+
+  get(key) {
+    return this.cache.getItem(key);
+  }
+
+  remove(key) {
+    this.keyTimeout.clearTimeout(key);
+    return this.cache.deleteItem(key);
+  }
+
+  async set(key, value) {
+    await this.cache.setItem(key, value);
+
+    if (typeof this.ttl === 'number') {
+      this.keyTimeout.updateTimeout(key, this.ttl, () => this.remove(key));
+    }
+  }
+};

classes/caching/key_timeout.js

@@ -0,0 +1,16 @@
+module.exports = class KeyTimeout {
+  constructor() {
+    this.timeoutHandleForKey = {};
+  }
+
+  clearTimeout(key) {
+    clearTimeout(this.timeoutHandleForKey[key]);
+  }
+
+  updateTimeout(key, durationMs, callback) {
+    this.clearTimeout(key);
+    this.timeoutHandleForKey[key] = setTimeout(() => {
+      callback();
+    }, durationMs);
+  }
+};

classes/caching/memory_cache.js

@@ -0,0 +1,26 @@
+const KeyTimeout = require('./key_timeout.js');
+
+module.exports = class MemoryCache {
+  constructor(options = {}) {
+    this.ttl = options.ttl;
+    this.keyTimeout = new KeyTimeout();
+    this.cache = {};
+  }
+
+  get(key) {
+    return this.cache[key];
+  }
+
+  remove(key) {
+    this.keyTimeout.clearTimeout(key);
+    delete this.cache[key];
+  }
+
+  set(key, value) {
+    this.cache[key] = value;
+
+    if (typeof this.ttl === 'number') {
+      this.keyTimeout.updateTimeout(key, this.ttl, () => this.remove(key));
+    }
+  }
+};