Add type definitions for insert-css (#31263)

* Add type definitions for insert-css

* Correct indentation in insert-css-tests.ts

* Make createElement calls consistent

* Use single quotes in import

types/insert-css/index.d.ts

@@ -0,0 +1,18 @@
+// Type definitions for insert-css 2.0
+// Project: https://github.com/substack/insert-css
+// Definitions by: Heye Vöcking <https://github.com/hvoecking>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+export interface InsertCssOptions {
+    container?: HTMLElement;
+    prepend?: boolean;
+}
+
+export interface InsertCssStyleElement extends HTMLStyleElement {
+    styleSheet?: CSSStyleSheet;
+}
+
+export function insertCss(
+    css: string,
+    options?: InsertCssOptions,
+): InsertCssStyleElement;

types/insert-css/insert-css-tests.ts

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+import { insertCss } from 'insert-css';
+
+insertCss('body{position:absolute}');
+
+insertCss('body{position:absolute}', {});
+
+insertCss('body{text-decoration:underline !important}', {
+    prepend: true,
+});
+
+insertCss('body{text-decoration:underline !important}', {
+    prepend: false,
+});
+
+insertCss('body{position:absolute}', {
+    container: document.createElement(''),
+});
+
+insertCss('body{text-decoration:underline !important}', {
+    prepend: true,
+    container: document.createElement(''),
+});
+
+insertCss('body{text-decoration:underline !important}', {
+    prepend: false,
+    container: document.createElement(''),
+});

types/insert-css/tsconfig.json

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+{
+    "compilerOptions": {
+        "baseUrl": "../",
+        "forceConsistentCasingInFileNames": true,
+        "lib": [
+            "dom",
+            "es6"
+        ],
+        "module": "commonjs",
+        "noEmit": true,
+        "noImplicitAny": true,
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "noImplicitThis": true,
+        "strictFunctionTypes": true,
+        "strictFunctionTypes": true,
+        "strictNullChecks": true,
+        "strictNullChecks": true,
+        "typeRoots": ["../"],
+        "types": []
+    },
+    "files": [
+        "index.d.ts",
+        "insert-css-tests.ts"
+    ]
+}

types/insert-css/tslint.json

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