Added map filter reduce foreach find with test and doc

Author: dev-parvej

README.md

@@ -0,0 +1,58 @@
+# go-js-array-methods
+
+This package is to implement javacript array methods which is missing in golang
+
+## Installation
+
+```
+go get github.com/dev-parvej/go-js-array-methods
+
+```
+
+## Usage
+
+```
+import js "github.com/dev-parvej/go-js-array-methods"
+
+type User struct {
+	Id   int
+	Name string
+}
+
+type Foo struct {
+	Bar string
+}
+
+users := []User{{Id: 10, Name: "Go"}, {Id: 11, Name: "Lang"}}
+
+```
+
+### Filter
+
+```
+filteredUsers := js.Filter(users, func(user User, index int) bool {
+    return user.Id == 10
+})
+
+```
+
+### Map
+
+```
+mapedUsers := js.Map(users, func(user User, index int) Foo {
+    return Foo{
+        Bar: fmt.Sprintf("%d %s", user.Id, user.Name),
+    }
+})
+
+```
+
+### Reduce 
+```
+numbers := []int{10, 11, 12, 13}
+sum := js.Reduce(numbers, func(s int, n int, i int) int {
+    return s + n
+}, 0)
+
+```
+

filter_test.go

@@ -0,0 +1,32 @@
+package js_array_method
+
+import (
+	"testing"
+)
+
+func TestFilterWithStructSlice(t *testing.T) {
+	users := []User{{Id: 10, Name: "Go"}, {Id: 11, Name: "Lang"}}
+
+	mapedUsers := Filter(users, func(user User, index int) bool {
+		return user.Id == 10
+	})
+	expected := 10
+
+	if mapedUsers[0].Id != 10 {
+		t.Errorf("Expected %d received %d", expected, mapedUsers[0].Id)
+	}
+}
+
+func TestFilterWithStringSlice(t *testing.T) {
+	var slices = []string{"Go", "Typescript", "Nodejs"}
+
+	ln := Filter(slices, func(ln string, index int) bool {
+		return ln == "Go"
+	})
+
+	expected := "Go"
+
+	if ln[0] != expected {
+		t.Errorf("Expected %s received %s", expected, ln[0])
+	}
+}

find_test.go

@@ -0,0 +1,31 @@
+package js_array_method
+
+import "testing"
+
+func TestFindWithStructSlice(t *testing.T) {
+	users := []User{{Id: 10, Name: "Go"}, {Id: 11, Name: "Lang"}}
+
+	user := Find(users, func(user User, index int) bool {
+		return user.Id == 10
+	})
+
+	expected := "Go"
+
+	if user.Name != expected {
+		t.Errorf("Expected %s received %s", expected, user.Name)
+	}
+}
+
+func TestFindWithStringSlice(t *testing.T) {
+	var slices = []string{"Go", "Typescript", "Nodejs"}
+
+	ln := Find(slices, func(ln string, index int) bool {
+		return ln == "Go"
+	})
+
+	expected := "Go"
+
+	if ln != expected {
+		t.Errorf("Expected %s received %s", expected, ln)
+	}
+}

forech_test.go

@@ -0,0 +1,24 @@
+package js_array_method
+
+import "testing"
+
+func TestForeachWithStructSlice(t *testing.T) {
+	users := []User{{Id: 10, Name: "Go"}, {Id: 11, Name: "Lang"}}
+
+	Foreach(users, func(user User, index int) {
+		if index == 0 && user.Name != "Go" {
+			t.Errorf("Expected %s received %s", "Go", user.Name)
+		}
+	})
+
+}
+
+func TestForeachWithStringSlice(t *testing.T) {
+	var slices = []string{"Go", "Typescript", "Nodejs"}
+
+	Foreach(slices, func(ln string, index int) {
+		if index == 0 && ln != "Go" {
+			t.Errorf("Expected %s received %s", "Go", ln)
+		}
+	})
+}

go.mod

@@ -0,0 +1,3 @@
+module github.com/dev-parvej/js_array_method
+
+go 1.19

js_array_method.go

@@ -0,0 +1,53 @@
+package js_array_method
+
+func Map[T any, U any](input []T, callback func(element T, index int) U) []U {
+	var output []U
+
+	for index, value := range input {
+		result := callback(value, index)
+
+		output = append(output, result)
+	}
+
+	return output
+}
+
+func Filter[T any](input []T, callback func(element T, index int) bool) []T {
+	var output []T
+
+	for index, value := range input {
+		if callback(value, index) {
+			output = append(output, value)
+		}
+	}
+
+	return output
+}
+
+func Reduce[T any, U any](input []T, callback func(pre U, current T, index int) U, initialValue U) U {
+	output := initialValue
+
+	for index, value := range input {
+		output = callback(output, value, index)
+	}
+
+	return output
+}
+
+func Find[T any](input []T, callback func(element T, index int) bool) T {
+	var item T
+	for index, value := range input {
+		if callback(value, index) {
+			item = value
+			break
+		}
+	}
+
+	return item
+}
+
+func Foreach[T any](input []T, callback func(element T, index int)) {
+	for index, value := range input {
+		callback(value, index)
+	}
+}

map_test.go

@@ -0,0 +1,54 @@
+package js_array_method
+
+import (
+	"fmt"
+	"testing"
+)
+
+type User struct {
+	Id   int
+	Name string
+}
+
+type Foo struct {
+	Bar string
+}
+
+func TestMapWithStructSlice(t *testing.T) {
+	users := []User{{Id: 10, Name: "Go"}, {Id: 11, Name: "Lang"}}
+
+	mapedUsers := Map(users, func(user User, index int) Foo {
+		return Foo{
+			Bar: fmt.Sprintf("%d %s", user.Id, user.Name),
+		}
+	})
+
+	expected := "10 Go"
+	if mapedUsers[0].Bar != expected {
+		t.Errorf("Expected %s received %s", expected, mapedUsers[0].Bar)
+	}
+	expected = "11 Lang"
+	if mapedUsers[1].Bar != expected {
+		t.Errorf("Expected %s received %s", expected, mapedUsers[1].Bar)
+	}
+}
+
+func TestMapWithStringSlice(t *testing.T) {
+	var slices = []string{"Go", "Typescript", "Nodejs"}
+
+	mappedSlice := Map(slices, func(ln string, index int) string {
+		return fmt.Sprintf("%d/%s", index, ln)
+	})
+
+	expected := "0/Go"
+
+	if mappedSlice[0] != expected {
+		t.Errorf("Expected %s received %s", expected, mappedSlice[0])
+	}
+
+	expected = "1/Typescript"
+
+	if mappedSlice[1] != expected {
+		t.Errorf("Expected %s received %s", expected, mappedSlice[1])
+	}
+}

reduce_test.go

@@ -0,0 +1,15 @@
+package js_array_method
+
+import "testing"
+
+func TestReduce(t *testing.T) {
+	numbers := []int{10, 11, 12, 13}
+
+	sum := Reduce(numbers, func(s int, n int, i int) int {
+		return s + n
+	}, 0)
+
+	if sum != 46 {
+		t.Errorf("Expected %d received %d", 46, sum)
+	}
+}