arr-pipe

A functional, declarative, and typesafe library for composing operations on arrays.

✨ Core Features

🔧 pipe

The main function that allows you to compose array operations together. Each operation in the pipe must take an array as input and return an array as output.

const lessThan = (num: number) => (arr: number[]) =>
  arr.filter((item) => item < num);

const operation = pipe(lessThan(8), lessThan(5));

operation([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
// [1, 2, 3, 4]

🔄 Higher Order Operations

union

Combines the results of two array operations, similar to a SET UNION operation.

const greaterThan = (num: number) => (arr: number[]) =>
  arr.filter((item) => item > num);
const lessThan = (num: number) => (arr: number[]) =>
  arr.filter((item) => item < num);
const operation = union(greaterThan(8), lessThan(5));

operation([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
// [1, 2, 3, 4, 9, 10]

intersection

Finds common elements between two array operations, similar to a SET INTERSECTION operation.

const greaterThan = (num: number) => (arr: number[]) =>
  arr.filter((item) => item > num);
const lessThan = (num: number) => (arr: number[]) =>
  arr.filter((item) => item < num);

const operation = intersection(greaterThan(8), lessThan(5));
operation([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
// []

🎯 Key Benefits

• Type Safety: Cannot construct pipes where output types don't match input types
• Array-Specific: Built specifically for array operations
• Composable: Easy to build complex pipelines from simple operations
• Flexible: Works with various data types (numbers, objects, strings, etc.)

🔍 Real World Use Cases

Perfect for building:

• Search result pipelines
• Recommendation feeds
• Data transformation chains
• Filter and sort combinations

🧪 Testing

Run the test suite:

yarn test

📚 Learn More

Check out the blog post for a detailed explanation of the implementation and use cases.

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Publishing New Versions

To publish a new version:

1. Update version in package.json
2. Create release notes in release-notes/v{version}.md
3. Commit changes
4. Run yarn deploy

This will publish to npm and create a GitHub release with the corresponding release notes.

📄 License

MIT License