A bash script to create a JEST-based NodeJS Typescript project for testing out new code fragments

createTSTestProj.sh

#!/bin/bash

# Function to prompt for a directory name if not provided
prompt_directory_name() {
  read -p "Enter the project directory name: " dir_name
  if [ -z "$dir_name" ]; then
    echo "Directory name cannot be empty. Please try again."
    prompt_directory_name
  fi
}

# Check if a directory name is passed as an argument
if [ -z "$1" ]; then
  prompt_directory_name
  dir_name=$dir_name
else
  dir_name=$1
fi

# Create the new directory
mkdir -p "$dir_name"

# Navigate into the new directory
cd "$dir_name" || exit

# Initialize a new Node.js project
npm init -y

# Install TypeScript and Jest along with necessary dependencies
npm install --save-dev typescript jest @types/jest ts-jest

# Initialize TypeScript configuration
npx tsc --init

# Write the tsconfig.json file with necessary configurations for ESM
cat <<EOT > tsconfig.json
{
  "compilerOptions": {
    "target": "ES2020",
    "module": "ESNext",
    "moduleResolution": "node",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "outDir": "./dist",
    "rootDir": "./src"
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules", "**/*.test.ts"]
}
EOT

# Initialize Jest configuration
npx ts-jest config:init

# Ensure the jest.config.js file has necessary settings
cat <<EOT > jest.config.js
export default {
  preset: 'ts-jest/presets/default-esm',
  testEnvironment: 'node',
  testMatch: ['**/?(*.)+(spec|test).[jt]s?(x)'],
  moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node'],
  extensionsToTreatAsEsm: ['.ts'],
  globals: {
    'ts-jest': {
      useESM: true
    }
  }
};
EOT

# Create project directory structure
mkdir src
mkdir __tests__

# Create a sample TypeScript file
cat <<EOT > src/mathFunctions.ts
export function add(a: number, b: number): number {
  return a + b;
}

export function subtract(a: number, b: number): number {
  return a - b;
}
EOT

# Create a sample test file
cat <<EOT > __tests__/mathFunctions.test.ts
import { add, subtract } from '../src/mathFunctions';

test('adds 1 + 2 to equal 3', () => {
  expect(add(1, 2)).toBe(3);
});

test('subtracts 5 - 2 to equal 3', () => {
  expect(subtract(5, 2)).toBe(3);
});
EOT

# Update package.json for ESM support
jq '.type = "module"' package.json > tmp.$$.json && mv tmp.$$.json package.json

# Add test script to package.json
npm set-script test "jest"

# Notify user of setup completion
echo "Project setup complete in directory $dir_name. You can add your own TypeScript files to the src directory and corresponding tests to the __tests__ directory."