improve types for String.split

package.json

@@ -72,6 +72,11 @@
       "types": "./dist/array-index-of.d.ts",
       "import": "./dist/array-index-of.mjs",
       "default": "./dist/array-index-of.js"
+    },
+    "./string-split": {
+      "types": "./dist/string-split.d.ts",
+      "import": "./dist/string-split.mjs",
+      "default": "./dist/string-split.js"
     }
   },
   "keywords": [],

src/entrypoints/recommended.d.ts

@@ -6,3 +6,4 @@
 /// <reference path="set-has.d.ts" />
 /// <reference path="map-has.d.ts" />
 /// <reference path="array-index-of.d.ts" />
+/// <reference path="string-split.d.ts" />

src/entrypoints/string-split.d.ts

@@ -0,0 +1,5 @@
+interface String {
+	split<Separator extends string, Limit extends number>(separator: Separator, limit?: Limit): Limit extends 0 ? []
+		: Separator extends '' ? string[]
+		: [string, ...string[]]
+}

src/tests/string-split.ts

@@ -0,0 +1,43 @@
+
+import { doNotExecute, Equal, Expect } from "./utils";
+
+doNotExecute(() => {
+	const result = ''.split('')
+	type tests = [Expect<Equal<typeof result, string[]>>];
+});
+
+doNotExecute(() => {
+	const result = ''.split('')[0]
+
+	type tests = [Expect<Equal<typeof result, string | undefined>>];
+});
+
+doNotExecute(() => {
+	const result = 'value'.split('test')
+
+	type tests = [Expect<Equal<typeof result, [string, ...string[]]>>];
+});
+
+doNotExecute(() => {
+	const result = 'value'.split('test')[0]
+
+	type tests = [Expect<Equal<typeof result, string>>];
+});
+
+doNotExecute(() => {
+	const result = 'value'.split('test')[1]
+
+	type tests = [Expect<Equal<typeof result, string | undefined>>];
+});
+
+doNotExecute(() => {
+	const result = 'value'.split('test', 0)
+
+	type tests = [Expect<Equal<typeof result, []>>];
+});
+
+doNotExecute(() => {
+	const result = 'value'.split('test', 1)
+
+	type tests = [Expect<Equal<typeof result, [string, ...string[]]>>];
+});

tsconfig.json

@@ -6,6 +6,7 @@
     "esModuleInterop": true, /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables 'allowSyntheticDefaultImports' for type compatibility. */
     "forceConsistentCasingInFileNames": true, /* Ensure that casing is correct in imports. */
     "strict": true, /* Enable all strict type-checking options. */
+    "noUncheckedIndexedAccess": true, /* Add undefined to a type when accessed using an index. */
   },
   "exclude": [
     "dist",