test: add onEvict validation tests for non-function callbacks

Author: avoidwork

coverage.txt

@@ -3,8 +3,8 @@
 ℹ file      | line % | branch % | funcs % | uncovered lines
 ℹ ----------------------------------------------------------
 ℹ src       |        |          |         | 
-ℹ  lru.js   |  99.70 |    98.54 |  100.00 | 534-535
+ℹ  lru.js   | 100.00 |    99.28 |  100.00 | 
 ℹ ----------------------------------------------------------
-ℹ all files |  99.70 |    98.54 |  100.00 | 
+ℹ all files | 100.00 |    99.28 |  100.00 | 
 ℹ ----------------------------------------------------------
 ℹ end of coverage report

tests/unit/lru.test.js

@@ -1292,6 +1292,17 @@ describe("LRU Cache", function () {
 			assert.equal(evictedItems[1].key, "b");
 			assert.equal(evictedItems[2].key, "c");
 		});
+
+		it("should throw TypeError if callback is not a function", function () {
+			assert.throws(() => cache.onEvict(undefined), {
+				message: "onEvict callback must be a function",
+			});
+			assert.throws(() => cache.onEvict(null), { message: "onEvict callback must be a function" });
+			assert.throws(() => cache.onEvict("not a function"), {
+				message: "onEvict callback must be a function",
+			});
+			assert.throws(() => cache.onEvict({}), { message: "onEvict callback must be a function" });
+		});
 	});
 
 	describe("sizeByTTL method", function () {