Vitest/Jest setup for TS

npm install --save-dev vitest @vitest/ui @types/node

// vitest.config.ts
import { defineConfig } from "vitest/config";
export default defineConfig({
  test: { globals: true }
});

// src/sum.ts
export const sum = (a: number, b: number) => a + b;

// src/sum.test.ts
import { sum } from "./sum";
import { describe, expect, it } from "vitest";

describe("sum", () => {
  it("adds numbers", () => {
    expect(sum(2, 3)).toBe(5);
  });
});

npm install --save-dev jest ts-jest @types/jest @types/node

// jest.config.js
module.exports = {
  preset: "ts-jest",
  testEnvironment: "node",
};

// src/sum.test.ts
import { sum } from "./sum";

test("adds numbers", () => {
  expect(sum(2, 3)).toBe(5);
});

// package.json (scripts)
{
  "scripts": {
    "test": "vitest",
    "test:ui": "vitest --ui",
    "test:jest": "jest"
  }
}