feat: add hooks for step lifecycle

ROADMAP.md

@@ -17,6 +17,7 @@ The development progress and future plans for PageAgent.
 - [x] **Free evaluation plan?**
 - [x] **Custom actions and HITL**
 - [ ] **Hooks and Events**
+	- [x] **Step lifecycle**
 - [ ] **Hijacking `page_open` event**
 - [ ] **Custom knowledge base and instructions**
 - [ ] **Black/white-list safeguard**

src/PageAgent.ts

@@ -156,6 +156,8 @@ export class PageAgent extends EventTarget {
 			let step = 0
 
 			while (true) {
+				if (this.config.onBeforeStep) await this.config.onBeforeStep.call(this, step)
+
 				console.group(`step: ${step + 1}`)
 
 				// abort
@@ -209,6 +211,8 @@ export class PageAgent extends EventTarget {
 				console.log(chalk.green('Step finished:'), actionName)
 				console.groupEnd()
 
+				if (this.config.onAfterStep) await this.config.onAfterStep.call(this, step, this.history)
+
 				step++
 				if (step > MAX_STEPS) {
 					this.#onDone('Step count exceeded maximum limit', false)

src/config/index.ts

@@ -1,3 +1,4 @@
+import type { AgentHistory, PageAgent } from '@/PageAgent'
 import type { DomConfig } from '@/dom'
 import type { SupportedLanguage } from '@/i18n'
 import type { PageAgentTool } from '@/tools'
@@ -47,6 +48,11 @@ export interface UIConfig {
 	 * }
 	 */
 	customTools?: Record<string, PageAgentTool | null>
+
+	// hooks
+
+	onBeforeStep?: (this: PageAgent, stepCnt: number) => Promise<void> | void
+	onAfterStep?: (this: PageAgent, stepCnt: number, history: AgentHistory[]) => Promise<void> | void
 }
 
 export type PageAgentConfig = LLMConfig & DomConfig & UIConfig