Functional programming context for Golang
if you want Dependency injection for Golang using plain functions, you are in the right place.
- 🤏 Tiny size and most of it is Golang generics
- 💉 Dependency injection without magic, only functions
- 🤌 Functions cached during workflow, no excess cost of CPU
- 💡 Smart type inference, only think about Context type and rest will be checked
- ♻️ Unit tests friendly, feel free to pass mocked function in the Context
- 📦 Tiny Redux like state manager also attached
import ( "github.com/samber/lo" "github.com/darky/context-fp-go" ) type Context struct { numbers []int } positiveNumbers := func(ctx *Context) []int { return lo.Filter(ctx.numbers, func(n int, i int) bool { return n > 0 }) } numbersPrefix := func(ctx *Context) string { return "Here is numbers:" } positiveNumbersAsString := Cfp2( &positiveNumbers, &numbersPrefix, func(ns []int, prefix string) string { ns2str := lo.Map(ns, func(n int, i int) string { return fmt.Sprintf("%v", n) }) return prefix + " " + strings.Join(ns2str, ",") }, ) assert.Equal(t, positiveNumbersAsString(&Context{ numbers: []int{-1, -5, 7, 0, 4}, }), "Here is numbers: 7,4", )import ( "github.com/samber/lo" "github.com/darky/context-fp-go" ) type Context struct { numbers []int } called := 0 positiveNumbers := func(ctx *Context) []int { called++ return lo.Filter(ctx.numbers, func(n int, i int) bool { return n > 0 }) } positiveNumbersLength := Cfp1( &positiveNumbers, func(ns []int) int { return len(ns) }, ) positiveNumbersAsString := Cfp2( &positiveNumbers, &positiveNumbersLength, func(ns []int, length int) string { ns2str := lo.Map(ns, func(n int, i int) string { return fmt.Sprintf("%v", n) }) return strings.Join(ns2str, ",") + "; length - " + fmt.Sprintf("%v", length) }, ) assert.Equal(t, positiveNumbersAsString(&Context{ numbers: []int{-1, -5, 7, 0, 4}, }), "7,4; length - 2", ) assert.Equal(t, called, 1)import ( "github.com/darky/context-fp-go" ) type User struct { name string } type Context struct { fetchUser func() User } fetchUserFromDB := func() User { // some production implementation } fetchUser := func(ctx *Context) User { if ctx.fetchUser == nil { return fetchUserFromDB() } return ctx.fetchUser() } helloWorldUser := Cfp1(&fetchUser, func(user User) string { return "Hello world, " + user.name }) assert.Equal( t, helloWorldUser(&Context{fetchUser: func() User { return User{name: "Vasya"} }}), "Hello world, Vasya", )import ( "github.com/darky/context-fp-go" ) type N struct { n int } type Context struct { incNumber int } numbers := func(ctx *Context) func(payload *N) []int { return Sfp( func(ns []int, payload *N) []int { return append(ns, payload.n+ctx.incNumber) }, []int{}, ) } addNumber1 := Cfp1(&numbers, func(ns func(payload *N) []int) []int { return ns(&N{1}) }) addNumber2 := Cfp1(&numbers, func(ns func(payload *N) []int) []int { return ns(&N{2}) }) addNumber3 := Cfp1(&numbers, func(ns func(payload *N) []int) []int { return ns(&N{3}) }) numbersToString := Cfp4( &numbers, &addNumber1, &addNumber2, &addNumber3, func(ns func(payload *N) []int, n1 []int, n2 []int, n3 []int) string { return strings.Join( lo.Map(ns(nil), func(n int, i int) string { return fmt.Sprintf("%v", n) }), ",", ) }, ) assert.Equal(t, numbersToString(&Context{incNumber: 1}), "2,3,4", )- context-fp - Functional programming context for TypeScript
- functx - Functional programming context for Gleam