Setup Jest in TypeScript-Babel-Starter

Clone TypeScript-Babel-Starter

git clone https://github.com/Microsoft/TypeScript-Babel-Starter.git PROJECT_NAME

Install and setup ts-jest

yarn add --dev jest typescript
yarn add --dev ts-jest @types/jest
yarn ts-jest config:init

Write some test case

Edit index.spec.ts

describe("add", () => {
  it("should add two numbers", () => {
    let result = 1 + 2
    expect(result).toBe(3);
  });
});

Test in console

yarn jest

Optional setting

Testing with breakpoint

node --inspect-brk node_modules/.bin/jest --runInBand

Setup debugger in VSCode

Create .vscode/launch.json

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "node",
      "request": "launch",
      "name": "Jest",
      "args": ["--inspect-brk", "node_modules/.bin/jest", "--runInBand"]
    },
    {
      "type": "node",
      "request": "launch",
      "name": "Jest single folder",
      "args": [
        "--inspect-brk",
        "node_modules/.bin/jest",
        "--runInBand",
        "src/path-to-your-folder"
      ]
    }
  ]
}

Written on December 17, 2018