improve eventhandler to detect changes automatically, return bool is no longer required

Author: marle3003

js/mokapi/on.go

@@ -1,6 +1,8 @@
 package mokapi
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
 	"github.com/dop251/goja"
 	"mokapi/js/util"
@@ -18,7 +20,13 @@ func (m *Module) On(event string, do goja.Value, vArgs goja.Value) {
 	}
 
 	f := func(args ...interface{}) (bool, error) {
-		r, err := m.loop.RunAsync(func(vm *goja.Runtime) (goja.Value, error) {
+		origin, err := getHashes(args...)
+		if err != nil {
+			return false, err
+		}
+
+		var r goja.Value
+		r, err = m.loop.RunAsync(func(vm *goja.Runtime) (goja.Value, error) {
 			call, _ := goja.AssertFunction(do)
 			var params []goja.Value
 			for _, v := range args {
@@ -35,7 +43,16 @@ func (m *Module) On(event string, do goja.Value, vArgs goja.Value) {
 			return false, err
 		}
 
-		return r.ToBoolean(), nil
+		if r != goja.Undefined() {
+			return r.ToBoolean(), nil
+		}
+
+		newHashes, err := getHashes(args...)
+		if err != nil {
+			return false, err
+		}
+
+		return haveChanges(origin, newHashes), nil
 	}
 
 	m.host.On(event, f, args.tags)
@@ -69,3 +86,25 @@ func getOnArgs(vm *goja.Runtime, args goja.Value) (onArgs, error) {
 	}
 	return onArgs{}, nil
 }
+
+func getHashes(args ...any) ([][]byte, error) {
+	var result [][]byte
+	for _, arg := range args {
+		b, err := json.Marshal(arg)
+		if err != nil {
+			return nil, fmt.Errorf("unable to marshal arg")
+		}
+		result = append(result, b)
+	}
+	return result, nil
+}
+
+func haveChanges(origin [][]byte, new [][]byte) bool {
+	for i, o := range origin {
+		n := new[i]
+		if !bytes.Equal(o, n) {
+			return true
+		}
+	}
+	return false
+}

js/mokapi/on_test.go

@@ -57,6 +57,24 @@ func TestModule_On(t *testing.T) {
 				r.Equal(t, true, b)
 			},
 		},
+		{
+			name: "event handler changes params but returns void",
+			test: func(t *testing.T, vm *goja.Runtime, host *enginetest.Host) {
+				var handler func(args ...interface{}) (bool, error)
+				host.OnFunc = func(evt string, do func(args ...interface{}) (bool, error), tags map[string]string) {
+					handler = do
+				}
+
+				_, err := vm.RunString(`
+					const m = require('mokapi')
+					m.on('http', (param) => { param['foo'] = false })
+				`)
+				r.NoError(t, err)
+				b, err := handler(map[string]bool{"foo": true})
+				r.NoError(t, err)
+				r.Equal(t, true, b)
+			},
+		},
 		{
 			name: "event handler throws error",
 			test: func(t *testing.T, vm *goja.Runtime, host *enginetest.Host) {

npm/types/index.d.ts

@@ -108,6 +108,10 @@ export interface EventHandler {
     smtp: SmtpEventHandler;
 }
 
+export type ChangeResult = boolean | void;
+
+export type EventHandlerResult = ChangeResult | Promise<ChangeResult>;
+
 /**
  * HttpEventHandler is a function that is executed when an HTTP event is triggered.
  * https://mokapi.io/docs/javascript-api/mokapi/eventhandler/httpeventhandler
@@ -122,7 +126,7 @@ export interface EventHandler {
  *   })
  * }
  */
-export type HttpEventHandler = (request: HttpRequest, response: HttpResponse) => boolean | Promise<boolean>;
+export type HttpEventHandler = (request: HttpRequest, response: HttpResponse) => EventHandlerResult;
 
 /**
  * HttpRequest is an object used by HttpEventHandler that contains request-specific
@@ -136,7 +140,7 @@ export interface HttpRequest {
     /** Represents a parsed URL. */
     readonly url: Url;
 
-    /** Body contains request body specified by OpenAPI request body. */
+    /** Body contains the request body specified by OpenAPI request body. */
     readonly body: any;
 
     /** Object contains path parameters specified by OpenAPI path parameters. */
@@ -204,7 +208,7 @@ export interface Url {
  *   })
  * }
  */
-export type KafkaEventHandler = (message: KafkaEventMessage) => boolean | Promise<boolean>;
+export type KafkaEventHandler = (message: KafkaEventMessage) => EventHandlerResult;
 
 /**
  * KafkaEventMessage is an object used by KafkaEventHandler that contains Kafka-specific message data.
@@ -243,7 +247,7 @@ export interface KafkaEventMessage {
  *   })
  * }
  */
-export type LdapEventHandler = (request: LdapSearchRequest, response: LdapSearchResponse) => boolean | Promise<boolean>;
+export type LdapEventHandler = (request: LdapSearchRequest, response: LdapSearchResponse) => EventHandlerResult;
 
 /**
  * LdapSearchRequest is an object used by LdapEventHandler that contains request-specific data.
@@ -343,7 +347,7 @@ export enum LdapResultStatus {
     SizeLimitExceeded = 4,
 }
 
-export type SmtpEventHandler = (record: SmtpEventMessage) => boolean | Promise<boolean>;
+export type SmtpEventHandler = (record: SmtpEventMessage) => EventHandlerResult;
 
 export interface SmtpEventMessage {
     server: string;