types: Add npm run check-types command

This allows to run typescript checking on the project to make sure the
types are functional.

package.json

@@ -26,6 +26,7 @@
     "dist": "npm run clean && npm run build:file && npm run lint && webpack --config build/webpack.conf.js && webpack --config build/webpack.common.js && webpack --config build/webpack.component.js && npm run build:utils && npm run build:umd && npm run build:theme",
     "i18n": "node build/bin/i18n.js",
     "lint": "eslint src/**/* test/**/* packages/**/* build/**/* --quiet",
+    "check-types": "tsc --noEmit -p .",
     "pub": "npm run bootstrap && sh build/git-release.sh && sh build/release.sh && node build/bin/gen-indices.js",
     "test": "npm run lint && npm run build:theme && cross-env CI_ENV=/dev/ BABEL_ENV=test karma start test/unit/karma.conf.js --single-run",
     "test:watch": "npm run build:theme && cross-env BABEL_ENV=test karma start test/unit/karma.conf.js"

tsconfig.json

@@ -0,0 +1,12 @@
+{
+  "compilerOptions": {
+    "strict": true,
+    "allowJs": true,
+    "noEmit": true,
+    "paths": {
+      "resize-observer-polyfill": ["./types/overrides/resize-observer-polyfill"]
+    }
+  },
+  "include": ["src/**/*", "packages/**/*", "types/**/*"],
+  "exclude": ["node_modules/**/*"]
+}

types/overrides/resize-observer-polyfill/index.d.ts

@@ -0,0 +1,36 @@
+// resize-observer-polyfill types conflict with typescript's own typings on typescript > 4.2.2
+// See https://github.com/que-etc/resize-observer-polyfill/issues/83
+//
+// So we override the typings for resize-observer-polyfill and remove the DOMRectReadOnly interface
+// definition
+// https://raw.githubusercontent.com/que-etc/resize-observer-polyfill/master/src/index.d.ts
+
+declare global {
+    interface ResizeObserverCallback {
+        (entries: ResizeObserverEntry[], observer: ResizeObserver): void
+    }
+
+    interface ResizeObserverEntry {
+        readonly target: Element;
+        readonly contentRect: DOMRectReadOnly;
+    }
+
+    interface ResizeObserver {
+        observe(target: Element): void;
+        unobserve(target: Element): void;
+        disconnect(): void;
+    }
+}
+
+declare var ResizeObserver: {
+    prototype: ResizeObserver;
+    new(callback: ResizeObserverCallback): ResizeObserver;
+}
+
+interface ResizeObserver {
+    observe(target: Element): void;
+    unobserve(target: Element): void;
+    disconnect(): void;
+}
+
+export default ResizeObserver;