perf: optimize entries, keys, and values methods (#386)

* perf: optimize entries, keys, and values methods

* fix: change LRUCache to LRUCacheWithDelete import

Author: cesco69

benchmarks/comparison-benchmark.js

@@ -30,7 +30,7 @@ try {
 try {
 	// Import from mnemonist using the correct export pattern
 	const mnemonistModule = await import("mnemonist");
-	MnemonistLRU = mnemonistModule.LRUCache;
+	MnemonistLRU = mnemonistModule.LRUCacheWithDelete;
 } catch (error) {
 	console.error("mnemonist not found. Run: npm install --no-save mnemonist");
 	console.error("Error:", error.message);

src/lru.js

@@ -119,7 +119,13 @@ export class LRU {
 	 * @since 11.1.0
 	 */
 	entries (keys = this.keys()) {
-		return keys.map(key => [key, this.get(key)]);
+		const result = new Array(keys.length);
+		for (let i = 0; i < keys.length; i++) {
+			const key = keys[i];
+			result[i] = [key, this.get(key)];
+		}
+
+		return result;
 	}
 
 	/**
@@ -296,11 +302,12 @@ export class LRU {
 	 * @since 9.0.0
 	 */
 	keys () {
-		const result = [];
+		const result = new Array(this.size);
 		let x = this.first;
+		let i = 0;
 
 		while (x !== null) {
-			result.push(x.key);
+			result[i++] = x.key;
 			x = x.next;
 		}
 
@@ -429,7 +436,12 @@ export class LRU {
 	 * @since 11.1.0
 	 */
 	values (keys = this.keys()) {
-		return keys.map(key => this.get(key));
+		const result = new Array(keys.length);
+		for (let i = 0; i < keys.length; i++) {
+			result[i] = this.get(keys[i]);
+		}
+
+		return result;
 	}
 }