diff --git a/package-lock.json b/package-lock.json
index 96e2f190..324d5d8a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -71,29 +71,6 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
-    "node_modules/@asamuzakjp/css-color": {
-      "version": "3.2.0",
-      "resolved": "https://registry.npmjs.org/@asamuzakjp/css-color/-/css-color-3.2.0.tgz",
-      "integrity": "sha512-K1A6z8tS3XsmCMM86xoWdn7Fkdn9m6RSVtocUrJYIwZnFVkng/PvkEoWtOWmP+Scc6saYWHWZYbndEEXxl24jw==",
-      "dev": true,
-      "license": "MIT",
-      "optional": true,
-      "dependencies": {
-        "@csstools/css-calc": "^2.1.3",
-        "@csstools/css-color-parser": "^3.0.9",
-        "@csstools/css-parser-algorithms": "^3.0.4",
-        "@csstools/css-tokenizer": "^3.0.3",
-        "lru-cache": "^10.4.3"
-      }
-    },
-    "node_modules/@asamuzakjp/css-color/node_modules/lru-cache": {
-      "version": "10.4.3",
-      "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-10.4.3.tgz",
-      "integrity": "sha512-JNAzZcXrCt42VGLuYz0zfAzDfAvJWW6AfYlDBQyDV5DClI2m5sAmK+OIO7s59XfsRsWHp02jAJrRadPRGTt6SQ==",
-      "dev": true,
-      "license": "ISC",
-      "optional": true
-    },
     "node_modules/@babel/code-frame": {
       "version": "7.29.7",
       "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.29.7.tgz",
@@ -650,6 +627,7 @@
       "dev": true,
       "license": "MIT"
     },
+<<<<<<< HEAD
     "node_modules/@csstools/color-helpers": {
       "version": "5.1.0",
       "resolved": "https://registry.npmjs.org/@csstools/color-helpers/-/color-helpers-5.1.0.tgz",
@@ -725,6 +703,8 @@
         "@csstools/css-tokenizer": "^3.0.4"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/@emnapi/core": {
       "version": "1.10.0",
       "resolved": "https://registry.npmjs.org/@emnapi/core/-/core-1.10.0.tgz",
@@ -4124,6 +4104,7 @@
         "node": ">=0.4.0"
       }
     },
+<<<<<<< HEAD
     "node_modules/agent-base": {
       "version": "7.1.4",
       "resolved": "https://registry.npmjs.org/agent-base/-/agent-base-7.1.4.tgz",
@@ -4135,6 +4116,8 @@
         "node": ">= 14"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/ajv": {
       "version": "6.15.0",
       "resolved": "https://registry.npmjs.org/ajv/-/ajv-6.15.0.tgz",
@@ -5213,6 +5196,7 @@
         "node": ">=4"
       }
     },
+<<<<<<< HEAD
     "node_modules/cssstyle": {
       "version": "4.6.0",
       "resolved": "https://registry.npmjs.org/cssstyle/-/cssstyle-4.6.0.tgz",
@@ -5228,6 +5212,8 @@
         "node": ">=18"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/csstype": {
       "version": "3.2.3",
       "resolved": "https://registry.npmjs.org/csstype/-/csstype-3.2.3.tgz",
@@ -5362,6 +5348,7 @@
       "dev": true,
       "license": "BSD-2-Clause"
     },
+<<<<<<< HEAD
     "node_modules/data-urls": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/data-urls/-/data-urls-5.0.0.tgz",
@@ -5377,6 +5364,8 @@
         "node": ">=18"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/data-view-buffer": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/data-view-buffer/-/data-view-buffer-1.0.2.tgz",
@@ -5459,6 +5448,7 @@
         }
       }
     },
+<<<<<<< HEAD
     "node_modules/decimal.js": {
       "version": "10.6.0",
       "resolved": "https://registry.npmjs.org/decimal.js/-/decimal.js-10.6.0.tgz",
@@ -5467,6 +5457,8 @@
       "license": "MIT",
       "optional": true
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/decimal.js-light": {
       "version": "2.5.1",
       "resolved": "https://registry.npmjs.org/decimal.js-light/-/decimal.js-light-2.5.1.tgz",
@@ -5686,6 +5678,7 @@
       "dev": true,
       "license": "MIT"
     },
+<<<<<<< HEAD
     "node_modules/entities": {
       "version": "6.0.1",
       "resolved": "https://registry.npmjs.org/entities/-/entities-6.0.1.tgz",
@@ -5700,6 +5693,8 @@
         "url": "https://github.com/fb55/entities?sponsor=1"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/error-ex": {
       "version": "1.3.4",
       "resolved": "https://registry.npmjs.org/error-ex/-/error-ex-1.3.4.tgz",
@@ -7105,6 +7100,7 @@
         "node": ">= 0.4"
       }
     },
+<<<<<<< HEAD
     "node_modules/html-encoding-sniffer": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/html-encoding-sniffer/-/html-encoding-sniffer-4.0.0.tgz",
@@ -7119,6 +7115,8 @@
         "node": ">=18"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/html-escaper": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/html-escaper/-/html-escaper-2.0.2.tgz",
@@ -7146,6 +7144,7 @@
         "node": ">=8.0.0"
       }
     },
+<<<<<<< HEAD
     "node_modules/http-proxy-agent": {
       "version": "7.0.2",
       "resolved": "https://registry.npmjs.org/http-proxy-agent/-/http-proxy-agent-7.0.2.tgz",
@@ -7176,6 +7175,8 @@
         "node": ">= 14"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/human-signals": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/human-signals/-/human-signals-5.0.0.tgz",
@@ -7195,6 +7196,7 @@
         "node": ">=20.0.0"
       }
     },
+<<<<<<< HEAD
     "node_modules/iconv-lite": {
       "version": "0.6.3",
       "resolved": "https://registry.npmjs.org/iconv-lite/-/iconv-lite-0.6.3.tgz",
@@ -7209,6 +7211,8 @@
         "node": ">=0.10.0"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/ignore": {
       "version": "5.3.2",
       "resolved": "https://registry.npmjs.org/ignore/-/ignore-5.3.2.tgz",
@@ -7632,6 +7636,7 @@
         "node": ">=8"
       }
     },
+<<<<<<< HEAD
     "node_modules/is-potential-custom-element-name": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/is-potential-custom-element-name/-/is-potential-custom-element-name-1.0.1.tgz",
@@ -7640,6 +7645,8 @@
       "license": "MIT",
       "optional": true
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/is-regex": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/is-regex/-/is-regex-1.2.1.tgz",
@@ -9998,6 +10005,7 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+<<<<<<< HEAD
     "node_modules/nwsapi": {
       "version": "2.2.23",
       "resolved": "https://registry.npmjs.org/nwsapi/-/nwsapi-2.2.23.tgz",
@@ -10006,6 +10014,8 @@
       "license": "MIT",
       "optional": true
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/oauth": {
       "version": "0.9.15",
       "resolved": "https://registry.npmjs.org/oauth/-/oauth-0.9.15.tgz",
@@ -10316,6 +10326,7 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+<<<<<<< HEAD
     "node_modules/parse5": {
       "version": "7.3.0",
       "resolved": "https://registry.npmjs.org/parse5/-/parse5-7.3.0.tgz",
@@ -10330,6 +10341,8 @@
         "url": "https://github.com/inikulin/parse5?sponsor=1"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/path-exists": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/path-exists/-/path-exists-4.0.0.tgz",
@@ -10579,7 +10592,6 @@
       "version": "2.3.2",
       "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
       "integrity": "sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==",
-      "dev": true,
       "hasInstallScript": true,
       "license": "MIT",
       "optional": true,
@@ -11292,6 +11304,7 @@
       "dev": true,
       "license": "MIT"
     },
+<<<<<<< HEAD
     "node_modules/rrweb-cssom": {
       "version": "0.8.0",
       "resolved": "https://registry.npmjs.org/rrweb-cssom/-/rrweb-cssom-0.8.0.tgz",
@@ -11300,6 +11313,8 @@
       "license": "MIT",
       "optional": true
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/run-parallel": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/run-parallel/-/run-parallel-1.2.0.tgz",
@@ -11379,6 +11394,7 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
+<<<<<<< HEAD
     "node_modules/safer-buffer": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/safer-buffer/-/safer-buffer-2.1.2.tgz",
@@ -11401,6 +11417,8 @@
         "node": ">=v12.22.7"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/scheduler": {
       "version": "0.23.2",
       "resolved": "https://registry.npmjs.org/scheduler/-/scheduler-0.23.2.tgz",
@@ -12105,6 +12123,7 @@
         "node": ">=12.0.0"
       }
     },
+<<<<<<< HEAD
     "node_modules/symbol-tree": {
       "version": "3.2.4",
       "resolved": "https://registry.npmjs.org/symbol-tree/-/symbol-tree-3.2.4.tgz",
@@ -12113,6 +12132,8 @@
       "license": "MIT",
       "optional": true
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/synckit": {
       "version": "0.11.12",
       "resolved": "https://registry.npmjs.org/synckit/-/synckit-0.11.12.tgz",
@@ -12372,6 +12393,7 @@
         "node": ">=14.0.0"
       }
     },
+<<<<<<< HEAD
     "node_modules/tldts": {
       "version": "6.1.86",
       "resolved": "https://registry.npmjs.org/tldts/-/tldts-6.1.86.tgz",
@@ -12394,6 +12416,8 @@
       "license": "MIT",
       "optional": true
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/tmpl": {
       "version": "1.0.5",
       "resolved": "https://registry.npmjs.org/tmpl/-/tmpl-1.0.5.tgz",
@@ -12414,6 +12438,7 @@
         "node": ">=8.0"
       }
     },
+<<<<<<< HEAD
     "node_modules/tough-cookie": {
       "version": "5.1.2",
       "resolved": "https://registry.npmjs.org/tough-cookie/-/tough-cookie-5.1.2.tgz",
@@ -12442,6 +12467,8 @@
         "node": ">=18"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/ts-api-utils": {
       "version": "2.5.0",
       "resolved": "https://registry.npmjs.org/ts-api-utils/-/ts-api-utils-2.5.0.tgz",
@@ -13049,6 +13076,7 @@
         }
       }
     },
+<<<<<<< HEAD
     "node_modules/w3c-xmlserializer": {
       "version": "5.0.0",
       "resolved": "https://registry.npmjs.org/w3c-xmlserializer/-/w3c-xmlserializer-5.0.0.tgz",
@@ -13063,6 +13091,8 @@
         "node": ">=18"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/walker": {
       "version": "1.0.8",
       "resolved": "https://registry.npmjs.org/walker/-/walker-1.0.8.tgz",
@@ -13073,6 +13103,7 @@
         "makeerror": "1.0.12"
       }
     },
+<<<<<<< HEAD
     "node_modules/webidl-conversions": {
       "version": "7.0.0",
       "resolved": "https://registry.npmjs.org/webidl-conversions/-/webidl-conversions-7.0.0.tgz",
@@ -13125,6 +13156,8 @@
         "node": ">=18"
       }
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/which": {
       "version": "2.0.2",
       "resolved": "https://registry.npmjs.org/which/-/which-2.0.2.tgz",
@@ -13386,6 +13419,7 @@
         "node": "^14.17.0 || ^16.13.0 || >=18.0.0"
       }
     },
+<<<<<<< HEAD
     "node_modules/ws": {
       "version": "8.21.0",
       "resolved": "https://registry.npmjs.org/ws/-/ws-8.21.0.tgz",
@@ -13428,6 +13462,8 @@
       "license": "MIT",
       "optional": true
     },
+=======
+>>>>>>> 498ad39 (test: add edge case coverage for dateDiffDays)
     "node_modules/y18n": {
       "version": "5.0.8",
       "resolved": "https://registry.npmjs.org/y18n/-/y18n-5.0.8.tgz",
diff --git a/test/dateDiffDays.test.ts b/test/dateDiffDays.test.ts
index 32983107..ab6a96b2 100644
--- a/test/dateDiffDays.test.ts
+++ b/test/dateDiffDays.test.ts
@@ -44,6 +44,25 @@ describe("dateUtils dateDiffDays", () => {
     expect(dateDiffDays("2025-01-01", "2024-01-01")).toBe(-366);
   });
 
+  it("returns positive day differences for non-consecutive dates", () => {
+    expect(dateDiffDays("2024-04-05", "2024-04-15")).toBe(10);
+  });
+
+  it("handles month boundary edge cases", () => {
+    expect(dateDiffDays("2024-04-30", "2024-05-01")).toBe(1);
+    expect(dateDiffDays("2024-05-31", "2024-06-01")).toBe(1);
+  });
+
+  it("handles leap year and non-leap year boundaries", () => {
+    expect(dateDiffDays("2024-02-28", "2024-03-01")).toBe(2);
+    expect(dateDiffDays("2023-02-28", "2023-03-01")).toBe(1);
+  });
+
+  it("returns NaN for invalid date input", () => {
+    expect(Number.isNaN(dateDiffDays("invalid-date", "2024-01-01"))).toBe(true);
+    expect(Number.isNaN(dateDiffDays("2024-01-01", "not-a-date"))).toBe(true);
+  });
+
   it("returns fractional days when times differ on same date", () => {
     const diff = dateDiffDays("2024-06-15T10:00:00Z", "2024-06-15T23:59:59Z");
     expect(diff).toBeGreaterThan(0);