Go Utils

Functional programming utilities for Go 1.21+ designed to complement stdlib's slices, maps, and cmp packages.

Why Go Utils?

Complementary to stdlib: Use slices.Index, slices.Contains, slices.Clone for basic operations. Use go-utils for functional patterns (Map, Filter, Reduce), LINQ-style operations (GroupBy, Partition), and utilities not in stdlib.

Type-safe with generics: All functions use Go 1.21+ generics with appropriate constraints for compile-time type safety.

Immutable by default: Functions don't mutate inputs. Operations return new values.

100% test coverage: Every function is comprehensively tested.

Installation

go get -u github.com/Goldziher/go-utils

Quick Examples

Functional Slice Operations

import "github.com/Goldziher/go-utils/sliceutils"

numbers := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

// Chain functional operations
evens := sliceutils.Filter(numbers, func(v, i int, s []int) bool {
    return v%2 == 0
})

doubled := sliceutils.Map(evens, func(v, i int, s []int) int {
    return v * 2
})

sum := sliceutils.Reduce(doubled, func(acc, v, i int, s []int) int {
    return acc + v
}, 0)
// Result: sum = 60 (2+4+6+8+10 doubled = 4+8+12+16+20 = 60)

LINQ-Style Operations

type User struct {
    Name string
    Age  int
    Role string
}

users := []User{
    {"Alice", 30, "admin"},
    {"Bob", 25, "user"},
    {"Charlie", 30, "user"},
}

// Group by age
byAge := sliceutils.GroupBy(users, func(u User) int { return u.Age })
// Result: map[int][]User{25: [{Bob 25 user}], 30: [{Alice 30 admin}, {Charlie 30 user}]}

// Partition by predicate
admins, regularUsers := sliceutils.Partition(users, func(u User) bool {
    return u.Role == "admin"
})

// Get distinct ages
ages := sliceutils.DistinctBy(users, func(u User) int { return u.Age })

Map Transformations

import "github.com/Goldziher/go-utils/maputils"

data := map[string]int{"apple": 5, "banana": 3, "cherry": 8}

// Extract keys and values
keys := maputils.Keys(data)     // []string{"apple", "banana", "cherry"}
values := maputils.Values(data) // []int{5, 3, 8}

// Filter map entries
filtered := maputils.Filter(data, func(k string, v int) bool {
    return v > 4
})
// Result: map[string]int{"apple": 5, "cherry": 8}

Type-Safe String Conversion

import "github.com/Goldziher/go-utils/stringutils"

// Stringify any type with options
hex := stringutils.Stringify(42, stringutils.Options{Base: 16})  // "2a"
float := stringutils.Stringify(3.14159, stringutils.Options{Precision: 2})  // "3.14"

// Stringify complex types
m := map[string]int{"a": 1, "b": 2}
str := stringutils.Stringify(m)  // "{a: 1, b: 2}"

Business Date Calculations

import "github.com/Goldziher/go-utils/dateutils"

// Add business days (skips weekends)
future := dateutils.AddBusinessDays(time.Now(), 5)

// Check date range overlap
overlaps := dateutils.Overlap(start1, end1, start2, end2)

// Calculate age
age := dateutils.Age(birthdate)

Packages

Package	Description	Key Functions
sliceutils	Functional and LINQ-style slice operations	Map, Filter, Reduce, GroupBy, Partition, Find
maputils	Map transformations	Keys, Values, Filter, Merge, Invert
stringutils	String manipulation	Stringify, ToCamelCase, ToSnakeCase, Truncate
structutils	Struct reflection utilities	ToMap, ForEach, FieldNames (tag-aware)
dateutils	Date/time utilities	AddBusinessDays, Overlap, Age, StartOfWeek
urlutils	URL and query string builders	QueryStringifyMap, QueryStringifyStruct
mathutils	Generic math operations	Clamp, InRange, Gcd, Lcm, IsPrime
ptrutils	Pointer utilities	ToPtr, Deref
excutils	Exception-style error handling	Panic, Try, Must

Documentation

Full documentation available at goldziher.github.io/go-utils

API reference at pkg.go.dev/github.com/Goldziher/go-utils

Contributing

Contributions are welcome! Please read the Contributing Guide before submitting PRs.

License

MIT License - see LICENSE for details.

Author

Na'aman Hirschfeld