_Underscore

underscore is a Go library providing useful functional programming helpers without extending any built-in objects.

It is mostly a port from the underscore.js library based on generics brought by Go 1.18.

Usage

📚 Follow this link for the documentation.

Install the library using

go get github.com/rjNemo/underscore@latest

Please check out the examples to see how to use the library.

package main

import (
 "fmt"
 u "github.com/rjNemo/underscore"
)

func main() {
 numbers := []int{1, 2, 3, 4, 5, 6, 7, 8, 9}
 // filter even numbers from the slice
 evens := u.Filter(numbers, func(n int) bool { return n%2 == 0 })
 // square every number in the slice
 squares := u.Map(evens, func(n int) int { return n * n })
 // reduce to the sum
 res := u.Reduce(squares, func(n, acc int) int { return n + acc }, 0)

 fmt.Println(res) // 120
}

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.

Prerequisites

You need at least go1.24 for development. The project is shipped with a Dockerfile based on go1.24.

If you prefer local development, navigate to the official download page and install version 1.24 or beyond.

Installing

First clone the repository

git clone https://github.com/rjNemo/underscore.git

Install dependencies

go mod download

And that's it.

Tests

To run the unit tests, you can simply run:

make test

Functions

underscore provides many of functions that support your favorite functional helpers

Collections

All
Any
Chunk
Contains
ContainsBy
Count
Difference
Drop
Each
Filter
Find
Flatmap
GroupBy
Intersection
Join / JoinProject
Last
Map
Max
Min
OrderBy
Partition
Range
Reduce
RemoveAt
Sum / SumMap
Unique
UniqueBy
UniqueInPlace
Zip

Pipe

Calling NewPipe will cause all future method calls to return wrapped values. When you've finished the computation, call Value to retrieve the final value.

Methods not returning a slice such as Reduce, All, Any, will break the Chain and return Value instantly.

Concurrency

ParallelMap(ctx, values, workers, fn): apply a function concurrently while preserving order and supporting context cancellation.
ParallelFilter(ctx, values, workers, fn): filter concurrently with order preserved and context support.

package main

import (
 "context"
 "fmt"
 u "github.com/rjNemo/underscore"
)

func main() {
 out, err := u.ParallelMap(context.Background(), []int{1, 2, 3, 4}, 4,
  func(ctx context.Context, n int) (int, error) { return n * n, nil },
 )
 fmt.Println(out, err) // [1 4 9 16] <nil>
}

// ParallelFilter example
package main

import (
 "context"
 "fmt"
 u "github.com/rjNemo/underscore"
)

func main() {
 out, err := u.ParallelFilter(context.Background(), []int{1,2,3,4,5}, 3,
  func(ctx context.Context, n int) (bool, error) { return n%2==0, nil },
 )
 fmt.Println(out, err) // [2 4] <nil>
}

Utilities

Ternary: conditional expression helper
ToPointer: convert values to pointers
SortSliceASC / SortSliceDESC: sort slices in ascending or descending order
Result, Ok, Err, ToResult: Result type for error handling
Tuple: generic tuple type for paired values

Subpackages

maps.Keys(m) / maps.Values(m): extract keys or values from maps
maps.Map(m, fn): transform map entries

Built With

Go - Build fast, reliable, and efficient software at scale

Contributing

Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.

Versioning

We use SemVer for versioning. For the versions available, see the tags on this repository.

Authors

Ruidy - Initial work - Ruidy

See also the list of contributors who participated in this project.

License

This project is licensed under the MIT License - see the LICENSE.md file for details

Acknowledgments

This project is largely inspired by Underscore.js library. Check out the original project if you don't already know it.

📚 underscore - Awesome Go Library for Functional

Detailed Description of underscore