feat: add new functions

function/function.go

@@ -6,6 +6,7 @@ package function
 
 import (
 	"reflect"
+	"sync"
 	"time"
 )
 
@@ -75,6 +76,7 @@ func Delay(delay time.Duration, fn interface{}, args ...interface{}) {
 }
 
 // Debounced creates a debounced function that delays invoking fn until after wait duration have elapsed since the last time the debounced function was invoked.
+// Deprecated: Use Debounce function instead.
 func Debounced(fn func(), duration time.Duration) func() {
 	// Catch programming error while constructing the closure
 	mustBeFunction(fn)
@@ -94,6 +96,74 @@ func Debounced(fn func(), duration time.Duration) func() {
 	return func() { timer.Reset(duration) }
 }
 
+// Debounce creates a debounced version of the provided function.
+func Debounce(fn func(), delay time.Duration) (debouncedFn func(), cancelFn func()) {
+	var (
+		timer *time.Timer
+		mu    sync.Mutex
+	)
+
+	debouncedFn = func() {
+		mu.Lock()
+		defer mu.Unlock()
+
+		if timer != nil {
+			timer.Stop()
+		}
+
+		timer = time.AfterFunc(delay, func() {
+			fn()
+		})
+	}
+
+	cancelFn = func() {
+		mu.Lock()
+		defer mu.Unlock()
+
+		if timer != nil {
+			timer.Stop()
+		}
+	}
+
+	return debouncedFn, cancelFn
+}
+
+// Throttle creates a throttled version of the provided function.
+// The returned function guarantees that it will only be invoked at most once per interval.
+func Throttle(fn func(), interval time.Duration) func() {
+	var (
+		timer   *time.Timer
+		lastRun time.Time
+		mu      sync.Mutex
+	)
+
+	return func() {
+		mu.Lock()
+		defer mu.Unlock()
+
+		now := time.Now()
+		if now.Sub(lastRun) >= interval {
+			fn()
+			lastRun = now
+			if timer != nil {
+				timer.Stop()
+				timer = nil
+			}
+		} else if timer == nil {
+			delay := interval - now.Sub(lastRun)
+
+			timer = time.AfterFunc(delay, func() {
+				mu.Lock()
+				defer mu.Unlock()
+
+				fn()
+				lastRun = time.Now()
+				timer = nil
+			})
+		}
+	}
+}
+
 // Schedule invoke function every duration time, util close the returned bool chan
 func Schedule(d time.Duration, fn interface{}, args ...interface{}) chan bool {
 	// Catch programming error while constructing the closure

function/function_test.go

@@ -43,7 +43,7 @@ func TestBefore(t *testing.T) {
 
 	var res []int64
 	type cb func(args ...interface{}) []reflect.Value
-	appendStr := func(i int, s string, fn cb) {
+	appendStr := func(i int, _ string, fn cb) {
 		v := fn(i)
 		res = append(res, v[0].Int())
 	}
@@ -148,3 +148,145 @@ func TestPipeline(t *testing.T) {
 
 	assert.Equal(36, f(2))
 }
+
+func TestDebounce(t *testing.T) {
+	assert := internal.NewAssert(t, "TestDebounce")
+
+	t.Run("Single call", func(t *testing.T) {
+		callCount := 0
+
+		debouncedFn, _ := Debounce(func() {
+			callCount++
+		}, 500*time.Millisecond)
+
+		debouncedFn()
+
+		time.Sleep(1 * time.Second)
+
+		assert.Equal(1, callCount)
+	})
+
+	t.Run("Multiple calls within debounce interval", func(t *testing.T) {
+		callCount := 0
+
+		debouncedFn, _ := Debounce(func() {
+			callCount++
+		}, 1*time.Second)
+
+		for i := 0; i < 5; i++ {
+			go func(index int) {
+				time.Sleep(time.Duration(index) * 200 * time.Millisecond)
+				debouncedFn()
+			}(i)
+		}
+
+		time.Sleep(2 * time.Second)
+
+		assert.Equal(1, callCount)
+	})
+
+	t.Run("Immediate consecutive calls", func(t *testing.T) {
+		callCount := 0
+
+		debouncedFn, _ := Debounce(func() {
+			callCount++
+		}, 500*time.Millisecond)
+
+		for i := 0; i < 10; i++ {
+			debouncedFn()
+			time.Sleep(50 * time.Millisecond)
+		}
+
+		time.Sleep(1 * time.Second)
+
+		assert.Equal(1, callCount)
+	})
+
+	t.Run("Cancel calls", func(t *testing.T) {
+		callCount := 0
+
+		debouncedFn, cancelFn := Debounce(func() {
+			callCount++
+		}, 500*time.Millisecond)
+
+		debouncedFn()
+
+		cancelFn()
+
+		time.Sleep(1 * time.Second)
+
+		assert.Equal(0, callCount)
+	})
+
+}
+
+func TestThrottle(t *testing.T) {
+	assert := internal.NewAssert(t, "TestThrottle")
+
+	t.Run("Single call", func(t *testing.T) {
+		callCount := 0
+
+		throttledFn := Throttle(func() {
+			callCount++
+		}, 1*time.Second)
+
+		throttledFn()
+
+		time.Sleep(100 * time.Millisecond)
+
+		assert.Equal(1, callCount)
+	})
+
+	t.Run("Multiple calls within throttle interval", func(t *testing.T) {
+		callCount := 0
+
+		throttledFn := Throttle(func() {
+			callCount++
+		}, 1*time.Second)
+
+		for i := 0; i < 5; i++ {
+			throttledFn()
+		}
+
+		time.Sleep(1 * time.Second)
+
+		assert.Equal(1, callCount)
+	})
+
+	t.Run("Mutiple calls space out throttle interval", func(t *testing.T) {
+		callCount := 0
+
+		throttledFn := Throttle(func() {
+			callCount++
+		}, 500*time.Millisecond)
+
+		throttledFn()
+		time.Sleep(600 * time.Millisecond)
+
+		throttledFn()
+		time.Sleep(600 * time.Millisecond)
+
+		throttledFn()
+
+		time.Sleep(1 * time.Second)
+
+		assert.Equal(3, callCount)
+	})
+
+	t.Run("Call function near the end of the interval", func(t *testing.T) {
+		callCount := 0
+
+		throttledFn := Throttle(func() {
+			callCount++
+		}, 1*time.Second)
+
+		throttledFn()
+		time.Sleep(900 * time.Millisecond)
+
+		throttledFn()
+		time.Sleep(200 * time.Millisecond)
+
+		assert.Equal(2, callCount)
+	})
+
+}