From 4ae7e5982922a36b87c4913f703c0cea2e8340fd Mon Sep 17 00:00:00 2001
From: dudaodong <lanliddd.2007@163.com>
Date: Fri, 17 Mar 2023 16:03:35 +0800
Subject: [PATCH] feat: add example for promise

---
 async/promise_example_test.go | 195 ++++++++++++++++++++++++++++++++++
 1 file changed, 195 insertions(+)
 create mode 100644 async/promise_example_test.go

diff --git a/async/promise_example_test.go b/async/promise_example_test.go
new file mode 100644
index 0000000..6b06df3
--- /dev/null
+++ b/async/promise_example_test.go
@@ -0,0 +1,195 @@
+package async
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/duke-git/lancet/v2/internal"
+)
+
+func ExampleNew() {
+	p := New(func(resolve func(string), reject func(error)) {
+		resolve("hello")
+	})
+
+	val, err := p.Await()
+	if err != nil {
+		return
+	}
+
+	fmt.Println(val)
+
+	// Output:
+	// hello
+}
+
+func ExampleThen() {
+	p1 := New(func(resolve func(string), reject func(error)) {
+		resolve("hello ")
+	})
+
+	p2 := Then(p1, func(s string) string {
+		return s + "world"
+	})
+
+	result, err := p2.Await()
+	if err != nil {
+		return
+	}
+
+	fmt.Println(result)
+
+	// Output:
+	// hello world
+}
+
+func ExamplePromise_Then() {
+	p1 := New(func(resolve func(string), reject func(error)) {
+		resolve("hello ")
+	})
+
+	p2 := p1.Then(func(s string) string {
+		return s + "world"
+	})
+
+	result, err := p2.Await()
+	if err != nil {
+		return
+	}
+
+	fmt.Println(result)
+
+	// Output:
+	// hello world
+}
+
+func ExampleCatch() {
+	p1 := New(func(resolve func(string), reject func(error)) {
+		err := errors.New("error1")
+		reject(err)
+	})
+
+	p2 := Catch(p1, func(err error) error {
+		e := errors.New("error2")
+		return internal.JoinError(err, e)
+	})
+
+	_, err := p1.Await()
+
+	fmt.Println(err.Error())
+
+	result2, err := p2.Await()
+
+	fmt.Println(result2)
+	fmt.Println(err.Error())
+
+	// Output:
+	// error1
+	//
+	// error1
+	// error2
+}
+
+func ExamplePromise_Catch() {
+	p1 := New(func(resolve func(string), reject func(error)) {
+		err := errors.New("error1")
+		reject(err)
+	})
+
+	p2 := p1.Catch(func(err error) error {
+		e := errors.New("error2")
+		return internal.JoinError(err, e)
+	})
+
+	_, err := p1.Await()
+
+	fmt.Println(err.Error())
+
+	result2, err := p2.Await()
+
+	fmt.Println(result2)
+	fmt.Println(err.Error())
+
+	// Output:
+	// error1
+	//
+	// error1
+	// error2
+}
+
+func ExampleAll() {
+	p1 := New(func(resolve func(string), reject func(error)) {
+		resolve("a")
+	})
+	p2 := New(func(resolve func(string), reject func(error)) {
+		resolve("b")
+	})
+	p3 := New(func(resolve func(string), reject func(error)) {
+		resolve("c")
+	})
+
+	pms := []*Promise[string]{p1, p2, p3}
+	p := All(pms)
+
+	result, err := p.Await()
+	if err != nil {
+		return
+	}
+
+	fmt.Println(result)
+
+	// Output:
+	// [a b c]
+}
+
+func ExampleAny() {
+	p1 := New(func(resolve func(string), reject func(error)) {
+		time.Sleep(time.Millisecond * 250)
+		resolve("fast")
+	})
+	p2 := New(func(resolve func(string), reject func(error)) {
+		time.Sleep(time.Millisecond * 500)
+		resolve("slow")
+	})
+	p3 := New(func(resolve func(string), reject func(error)) {
+		reject(errors.New("error"))
+	})
+
+	pms := []*Promise[string]{p1, p2, p3}
+	p := Any(pms)
+
+	result, err := p.Await()
+	if err != nil {
+		return
+	}
+
+	fmt.Println(result)
+
+	// Output:
+	// fast
+}
+
+func ExampleRace() {
+	p1 := New(func(resolve func(string), reject func(error)) {
+		time.Sleep(time.Millisecond * 100)
+		resolve("fast")
+	})
+	p2 := New(func(resolve func(string), reject func(error)) {
+		time.Sleep(time.Millisecond * 300)
+		resolve("slow")
+	})
+
+	pms := []*Promise[string]{p1, p2}
+	p := Race(pms)
+
+	result, err := p.Await()
+	if err != nil {
+		return
+	}
+
+	fmt.Println(result)
+
+	// Output:
+	// fast
+}