playwright-page-object-model（Playwright page object model 搜索）

Playwright Page Object Model

Master the Page Object Model (POM) pattern to create maintainable, reusable, and scalable test automation code. This skill covers modern Playwright patterns including component-based architecture, locator strategies, and app actions.

Core POM Principles

Single Responsibility

Each page object should represent one page or component with a single, well-defined responsibility.

Encapsulation

Hide implementation details and expose only meaningful actions and assertions.

Reusability

Create reusable components that can be composed into larger page objects.

Maintainability

When UI changes, update page objects in one place rather than across multiple tests.

Basic Page Object Pattern

Simple Page Object

// pages/login-page.ts
import { Page, Locator } from '@playwright/test';

export class LoginPage {
  readonly page: Page;
  readonly emailInput: Locator;
  readonly passwordInput: Locator;
  readonly loginButton: Locator;
  readonly errorMessage: Locator;

  constructor(page: Page) {
    this.page = page;
    this.emailInput = page.getByLabel('Email');
    this.passwordInput = page.getByLabel('Password');
    this.loginButton = page.getByRole('button', { name: 'Login' });
    this.errorMessage = page.getByRole('alert');
  }

  async goto() {
    await this.page.goto('/login');
  }

  async login(email: string, password: string) {
    await this.emailInput.fill(email);
    await this.passwordInput.fill(password);
    await this.loginButton.click();
  }

  async getErrorMessage() {
    return await this.errorMessage.textContent();
  }
}

Using Page Object in Tests

// tests/login.spec.ts
import { test, expect } from '@playwright/test';
import { LoginPage } from '../pages/login-page';

test.describe('Login', () => {
  test('should login successfully', async ({ page }) => {
    const loginPage = new LoginPage(page);
    await loginPage.goto();
    await loginPage.login('user@example.com', 'password123');

    await expect(page).toHaveURL('/dashboard');
  });

  test('should show error on invalid credentials', async ({ page }) => {
    const loginPage = new LoginPage(page);
    await loginPage.goto();
    await loginPage.login('user@example.com', 'wrongpassword');

    const error = await loginPage.getErrorMessage();
    expect(error).toContain('Invalid credentials');
  });
});

Locator Strategies

Recommended Locator Priority

1. User-visible locators (getByRole, getByText, getByLabel)
2. Test IDs (getByTestId)
3. CSS/XPath (only as last resort)

User-Visible Locators

export class HomePage {
  readonly page: Page;

  constructor(page: Page) {
    this.page = page;
  }

  // By role (ARIA role)
  get searchButton() {
    return this.page.getByRole('button', { name: 'Search' });
  }

  // By label (form inputs)
  get searchInput() {
    return this.page.getByLabel('Search products');
  }

  // By text
  get welcomeMessage() {
    return this.page.getByText('Welcome back');
  }

  // By placeholder
  get emailInput() {
    return this.page.getByPlaceholder('Enter your email');
  }

  // By alt text (images)
  get logo() {
    return this.page.getByAltText('Company Logo');
  }

  // By title
  get helpIcon() {
    return this.page.getByTitle('Help');
  }
}

Test ID Locators

// Component with test IDs
// <button data-testid="submit-button">Submit</button>

export class FormPage {
  readonly page: Page;

  constructor(page: Page) {
    this.page = page;
  }

  get submitButton() {
    return this.page.getByTestId('submit-button');
  }

  get formContainer() {
    return this.page.getByTestId('form-container');
  }
}

Locator Chaining

export class ProductPage {
  readonly page: Page;

  constructor(page: Page) {
    this.page = page;
  }

  // Chain locators for specificity
  get priceInCart() {
    return this.page
      .getByTestId('shopping-cart')
      .getByRole('cell', { name: 'Price' });
  }

  // Filter locators
  getProductByName(name: string) {
    return this.page
      .getByRole('listitem')
      .filter({ hasText: name });
  }

  // Nth element
  get firstProduct() {
    return this.page.getByRole('article').nth(0);
  }
}

Component-Based Architecture

Reusable Component Objects

// components/navigation.ts
export class Navigation {
  readonly page: Page;
  readonly homeLink: Locator;
  readonly productsLink: Locator;
  readonly cartLink: Locator;
  readonly profileMenu: Locator;

  constructor(page: Page) {
    this.page = page;
    this.homeLink = page.getByRole('link', { name: 'Home' });
    this.productsLink = page.getByRole('link', { name: 'Products' });
    this.cartLink = page.getByRole('link', { name: 'Cart' });
    this.profileMenu = page.getByRole('button', { name: 'Profile' });
  }

  async navigateToHome() {
    await this.homeLink.click();
  }

  async navigateToProducts() {
    await this.productsLink.click();
  }

  async navigateToCart() {
    await this.cartLink.click();
  }

  async openProfileMenu() {
    await this.profileMenu.click();
  }
}

Composing Page Objects with Components

// pages/base-page.ts
import { Page } from '@playwright/test';
import { Navigation } from '../components/navigation';
import { Footer } from '../components/footer';

export class BasePage {
  readonly page: Page;
  readonly navigation: Navigation;
  readonly footer: Footer;

  constructor(page: Page) {
    this.page = page;
    this.navigation = new Navigation(page);
    this.footer = new Footer(page);
  }
}

// pages/product-page.ts
import { BasePage } from './base-page';
import { Page } from '@playwright/test';

export class ProductPage extends BasePage {
  readonly addToCartButton: Locator;
  readonly productTitle: Locator;
  readonly productPrice: Locator;

  constructor(page: Page) {
    super(page);
    this.addToCartButton = page.getByRole('button', { name: 'Add to Cart' });
    this.productTitle = page.getByRole('heading', { level: 1 });
    this.productPrice = page.getByTestId('product-price');
  }

  async goto(productId: string) {
    await this.page.goto(`/products/${productId}`);
  }

  async addToCart() {
    await this.addToCartButton.click();
    // Wait for cart update
    await this.page.waitForResponse(
      (response) => response.url().includes('/api/cart')
    );
  }

  async getProductTitle() {
    return await this.productTitle.textContent();
  }

  async getProductPrice() {
    const text = await this.productPrice.textContent();
    return parseFloat(text?.replace('$', '') || '0');
  }
}

Modal and Dialog Components

// components/modal.ts
export class Modal {
  readonly page: Page;
  readonly container: Locator;
  readonly closeButton: Locator;
  readonly title: Locator;

  constructor(page: Page) {
    this.page = page;
    this.container = page.getByRole('dialog');
    this.closeButton = this.container.getByRole('button', { name: 'Close' });
    this.title = this.container.getByRole('heading');
  }

  async isVisible() {
    return await this.container.isVisible();
  }

  async getTitle() {
    return await this.title.textContent();
  }

  async close() {
    await this.closeButton.click();
    await this.container.waitFor({ state: 'hidden' });
  }
}

// components/confirmation-modal.ts
import { Modal } from './modal';
import { Page } from '@playwright/test';

export class ConfirmationModal extends Modal {
  readonly confirmButton: Locator;
  readonly cancelButton: Locator;
  readonly message: Locator;

  constructor(page: Page) {
    super(page);
    this.confirmButton = this.container.getByRole('button', {
      name: 'Confirm',
    });
    this.cancelButton = this.container.getByRole('button', {
      name: 'Cancel',
    });
    this.message = this.container.getByTestId('modal-message');
  }

  async confirm() {
    await this.confirmButton.click();
    await this.container.waitFor({ state: 'hidden' });
  }

  async cancel() {
    await this.cancelButton.click();
    await this.container.waitFor({ state: 'hidden' });
  }

  async getMessage() {
    return await this.message.textContent();
  }
}

App Actions Pattern

High-Level Actions

// pages/app-actions.ts
import { Page } from '@playwright/test';
import { LoginPage } from './login-page';
import { ProductPage } from './product-page';

export class AppActions {
  readonly page: Page;

  constructor(page: Page) {
    this.page = page;
  }

  async login(email: string, password: string) {
    const loginPage = new LoginPage(this.page);
    await loginPage.goto();
    await loginPage.login(email, password);
    await this.page.waitForURL('/dashboard');
  }

  async addProductToCart(productId: string) {
    const productPage = new ProductPage(this.page);
    await productPage.goto(productId);
    await productPage.addToCart();
  }

  async completeCheckout(paymentDetails: PaymentDetails) {
    await this.page.goto('/checkout');
    await this.fillShippingInfo(paymentDetails.shipping);
    await this.fillPaymentInfo(paymentDetails.payment);
    await this.page.getByRole('button', { name: 'Place Order' }).click();
    await this.page.waitForURL('/order-confirmation');
  }

  private async fillShippingInfo(shipping: ShippingInfo) {
    await this.page.getByLabel('Full Name').fill(shipping.name);
    await this.page.getByLabel('Address').fill(shipping.address);
    await this.page.getByLabel('City').fill(shipping.city);
    await this.page.getByLabel('Postal Code').fill(shipping.postalCode);
  }

  private async fillPaymentInfo(payment: PaymentInfo) {
    await this.page.getByLabel('Card Number').fill(payment.cardNumber);
    await this.page.getByLabel('Expiry Date').fill(payment.expiry);
    await this.page.getByLabel('CVV').fill(payment.cvv);
  }
}

interface PaymentDetails {
  shipping: ShippingInfo;
  payment: PaymentInfo;
}

interface ShippingInfo {
  name: string;
  address: string;
  city: string;
  postalCode: string;
}

interface PaymentInfo {
  cardNumber: string;
  expiry: string;
  cvv: string;
}

Using App Actions in Tests

// tests/checkout.spec.ts
import { test, expect } from '@playwright/test';
import { AppActions } from '../pages/app-actions';

test('should complete checkout flow', async ({ page }) => {
  const app = new AppActions(page);

  await app.login('user@example.com', 'password123');
  await app.addProductToCart('product-123');
  await app.completeCheckout({
    shipping: {
      name: 'John Doe',
      address: '123 Main St',
      city: 'New York',
      postalCode: '10001',
    },
    payment: {
      cardNumber: '4111111111111111',
      expiry: '12/25',
      cvv: '123',
    },
  });

  await expect(page.getByText('Order confirmed')).toBeVisible();
});

Advanced Patterns

Generic Table Component

// components/table.ts
export class Table {
  readonly page: Page;
  readonly container: Locator;

  constructor(page: Page, testId?: string) {
    this.page = page;
    this.container = testId
      ? page.getByTestId(testId)
      : page.getByRole('table');
  }

  async getHeaders() {
    const headers = await this.container
      .getByRole('columnheader')
      .allTextContents();
    return headers;
  }

  async getRowCount() {
    return await this.container.getByRole('row').count() - 1; // Exclude header
  }

  async getRow(index: number) {
    return this.container.getByRole('row').nth(index + 1); // Skip header
  }

  async getCellValue(row: number, column: number) {
    const rowLocator = await this.getRow(row);
    const cell = rowLocator.getByRole('cell').nth(column);
    return await cell.textContent();
  }

  async getCellByColumnName(row: number, columnName: string) {
    const headers = await this.getHeaders();
    const columnIndex = headers.indexOf(columnName);
    if (columnIndex === -1) {
      throw new Error(`Column "${columnName}" not found`);
    }
    return await this.getCellValue(row, columnIndex);
  }

  async findRowByValue(columnName: string, value: string) {
    const headers = await this.getHeaders();
    const columnIndex = headers.indexOf(columnName);
    const rowCount = await this.getRowCount();

    for (let i = 0; i < rowCount; i++) {
      const cellValue = await this.getCellValue(i, columnIndex);
      if (cellValue === value) {
        return await this.getRow(i);
      }
    }

    return null;
  }
}

Form Component with Validation

// components/form.ts
export class Form {
  readonly page: Page;
  readonly container: Locator;
  readonly submitButton: Locator;

  constructor(page: Page, formTestId: string) {
    this.page = page;
    this.container = page.getByTestId(formTestId);
    this.submitButton = this.container.getByRole('button', {
      name: /submit|save|create/i,
    });
  }

  async fillField(label: string, value: string) {
    await this.container.getByLabel(label).fill(value);
  }

  async selectOption(label: string, value: string) {
    await this.container.getByLabel(label).selectOption(value);
  }

  async checkCheckbox(label: string) {
    await this.container.getByLabel(label).check();
  }

  async uncheckCheckbox(label: string) {
    await this.container.getByLabel(label).uncheck();
  }

  async submit() {
    await this.submitButton.click();
  }

  async getFieldError(label: string) {
    const field = this.container.getByLabel(label);
    const fieldId = await field.getAttribute('id');
    const error = this.container.locator(`[aria-describedby="${fieldId}"]`);
    return await error.textContent();
  }

  async hasError(label: string) {
    const error = await this.getFieldError(label);
    return error !== null && error.trim() !== '';
  }

  async getFormErrors() {
    const errors = await this.container
      .locator('[role="alert"]')
      .allTextContents();
    return errors.filter((e) => e.trim() !== '');
  }
}

Waiting Strategies in Page Objects

export class DashboardPage {
  readonly page: Page;
  readonly loadingSpinner: Locator;
  readonly dataTable: Locator;

  constructor(page: Page) {
    this.page = page;
    this.loadingSpinner = page.getByTestId('loading-spinner');
    this.dataTable = page.getByRole('table');
  }

  async goto() {
    await this.page.goto('/dashboard');
    await this.waitForPageLoad();
  }

  async waitForPageLoad() {
    // Wait for loading spinner to disappear
    await this.loadingSpinner.waitFor({ state: 'hidden' });

    // Wait for data to load
    await this.dataTable.waitFor({ state: 'visible' });

    // Wait for network idle
    await this.page.waitForLoadState('networkidle');
  }

  async refreshData() {
    const refreshButton = this.page.getByRole('button', { name: 'Refresh' });
    await refreshButton.click();

    // Wait for API response
    await this.page.waitForResponse(
      (response) =>
        response.url().includes('/api/dashboard') && response.status() === 200
    );

    await this.waitForPageLoad();
  }
}

Handling Dynamic Content

Lists and Collections

export class ProductListPage {
  readonly page: Page;
  readonly productCards: Locator;

  constructor(page: Page) {
    this.page = page;
    this.productCards = page.getByTestId('product-card');
  }

  async goto() {
    await this.page.goto('/products');
  }

  async getProductCount() {
    return await this.productCards.count();
  }

  async getProductCard(index: number) {
    return this.productCards.nth(index);
  }

  async getProductCardByName(name: string) {
    return this.productCards.filter({ hasText: name }).first();
  }

  async getAllProductNames() {
    const names = await this.productCards
      .locator('h3')
      .allTextContents();
    return names;
  }

  async clickProduct(name: string) {
    const card = await this.getProductCardByName(name);
    await card.click();
  }

  async addToCartByName(name: string) {
    const card = await this.getProductCardByName(name);
    await card.getByRole('button', { name: 'Add to Cart' }).click();
  }
}

Search and Filter

export class SearchPage {
  readonly page: Page;
  readonly searchInput: Locator;
  readonly searchButton: Locator;
  readonly results: Locator;
  readonly filters: Locator;

  constructor(page: Page) {
    this.page = page;
    this.searchInput = page.getByRole('searchbox');
    this.searchButton = page.getByRole('button', { name: 'Search' });
    this.results = page.getByTestId('search-results');
    this.filters = page.getByTestId('filters');
  }

  async search(query: string) {
    await this.searchInput.fill(query);
    await this.searchButton.click();
    await this.waitForResults();
  }

  async applyFilter(filterName: string, value: string) {
    await this.filters
      .getByRole('button', { name: filterName })
      .click();
    await this.page
      .getByRole('checkbox', { name: value })
      .check();
    await this.waitForResults();
  }

  async getResultCount() {
    const countText = await this.results
      .getByTestId('result-count')
      .textContent();
    return parseInt(countText?.match(/\d+/)?.[0] || '0');
  }

  private async waitForResults() {
    await this.page.waitForResponse(
      (response) => response.url().includes('/api/search')
    );
    await this.results.getByTestId('result-item').first().waitFor();
  }
}

Type-Safe Page Objects

Using TypeScript Interfaces

// types/user.ts
export interface User {
  email: string;
  password: string;
  firstName?: string;
  lastName?: string;
}

export interface Product {
  id: string;
  name: string;
  price: number;
  description?: string;
}

// pages/registration-page.ts
import { User } from '../types/user';

export class RegistrationPage {
  readonly page: Page;

  constructor(page: Page) {
    this.page = page;
  }

  async goto() {
    await this.page.goto('/register');
  }

  async register(user: User) {
    await this.page.getByLabel('Email').fill(user.email);
    await this.page.getByLabel('Password').fill(user.password);

    if (user.firstName) {
      await this.page.getByLabel('First Name').fill(user.firstName);
    }

    if (user.lastName) {
      await this.page.getByLabel('Last Name').fill(user.lastName);
    }

    await this.page.getByRole('button', { name: 'Register' }).click();
  }
}

Builder Pattern for Test Data

// builders/user-builder.ts
import { User } from '../types/user';

export class UserBuilder {
  private user: Partial<User> = {};

  withEmail(email: string): this {
    this.user.email = email;
    return this;
  }

  withPassword(password: string): this {
    this.user.password = password;
    return this;
  }

  withName(firstName: string, lastName: string): this {
    this.user.firstName = firstName;
    this.user.lastName = lastName;
    return this;
  }

  build(): User {
    if (!this.user.email || !this.user.password) {
      throw new Error('Email and password are required');
    }
    return this.user as User;
  }
}

// tests/registration.spec.ts
import { UserBuilder } from '../builders/user-builder';
import { RegistrationPage } from '../pages/registration-page';

test('should register new user', async ({ page }) => {
  const user = new UserBuilder()
    .withEmail('newuser@example.com')
    .withPassword('SecurePass123!')
    .withName('John', 'Doe')
    .build();

  const registrationPage = new RegistrationPage(page);
  await registrationPage.goto();
  await registrationPage.register(user);

  await expect(page).toHaveURL('/welcome');
});

When to Use This Skill

• Creating new page objects for test automation
• Refactoring existing tests to use Page Object Model
• Building reusable component libraries for tests
• Implementing app actions for complex user flows
• Standardizing locator strategies across a test suite
• Creating type-safe page objects with TypeScript
• Designing maintainable test architecture
• Handling dynamic content and complex UI interactions
• Building form and table abstractions
• Establishing page object patterns for a team

Resources

• Playwright Locators: https://playwright.dev/docs/locators
• Playwright Page Object Models: https://playwright.dev/docs/pom
• Playwright Best Practices: https://playwright.dev/docs/best-practices