feat(to-slug-case): new type definition (#43404)

Types for utility function:
- definition file
- test

https://www.npmjs.com/package/to-slug-case

Thanks!

types/to-slug-case/index.d.ts

@@ -0,0 +1,8 @@
+// Type definitions for to-slug-case 1.0
+// Project: https://github.com/ianstormtaylor/to-slug-case
+// Definitions by: Piotr Błażejewicz <https://github.com/peterblazejewicz>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+declare function toSlugCase(str: string): string;
+
+export = toSlugCase;

types/to-slug-case/to-slug-case-tests.ts

@@ -0,0 +1,3 @@
+import toSlugCase = require('to-slug-case');
+
+toSlugCase('camelCase'); // $ExpectType string

types/to-slug-case/tsconfig.json

@@ -0,0 +1,23 @@
+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": [
+            "es6"
+        ],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictFunctionTypes": true,
+        "strictNullChecks": true,
+        "baseUrl": "../",
+        "typeRoots": [
+            "../"
+        ],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": [
+        "index.d.ts",
+        "to-slug-case-tests.ts"
+    ]
+}

types/to-slug-case/tslint.json

@@ -0,0 +1 @@
+{ "extends": "dtslint/dt.json" }