Added 31

Author: mattpocock

src/05-external-libraries/26.5-override-external-lib-types.problem.ts

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+// TODO
+
+export {};

src/07-challenges/31-merge-dynamic-object-with-global.problem.ts

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+import { Equal, Expect } from "../helpers/type-utils";
+
+const addAllOfThisToWindow = {
+  add: (a: number, b: number) => a + b,
+  subtract: (a: number, b: number) => a - b,
+  multiply: (a: number, b: number) => a * b,
+  divide: (a: number, b: number) => a / b,
+};
+
+Object.assign(window, addAllOfThisToWindow);
+
+type tests = [
+  Expect<Equal<typeof window.add, (a: number, b: number) => number>>,
+  Expect<Equal<typeof window.subtract, (a: number, b: number) => number>>,
+  Expect<Equal<typeof window.multiply, (a: number, b: number) => number>>,
+  Expect<Equal<typeof window.divide, (a: number, b: number) => number>>,
+];

src/07-challenges/31-merge-dynamic-object-with-global.solution.ts

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+import { Equal, Expect } from "../helpers/type-utils";
+
+const addAllOfThisToWindow = {
+  addSolution: (a: number, b: number) => a + b,
+  subtractSolution: (a: number, b: number) => a - b,
+  multiplySolution: (a: number, b: number) => a * b,
+  divideSolution: (a: number, b: number) => a / b,
+};
+
+Object.assign(window, addAllOfThisToWindow);
+
+declare global {
+  type AddAllOfThisToWindowSolution = typeof addAllOfThisToWindow;
+
+  interface Window extends AddAllOfThisToWindowSolution {}
+}
+
+type tests = [
+  Expect<Equal<typeof window.addSolution, (a: number, b: number) => number>>,
+  Expect<
+    Equal<typeof window.subtractSolution, (a: number, b: number) => number>
+  >,
+  Expect<
+    Equal<typeof window.multiplySolution, (a: number, b: number) => number>
+  >,
+  Expect<Equal<typeof window.divideSolution, (a: number, b: number) => number>>
+];