11. JavaScript Design Patterns for Test Automation

Centralized Configuration & Constants

Never hardcode raw timeouts or base URLs inside test files:

// config/constants.js
export const TIMEOUTS = Object.freeze({
  SHORT: 5000,
  MEDIUM: 15000,
  LONG: 30000,
});
export const ENVIRONMENTS = {
  staging: {
    baseUrl: "https://staging.targetqa.com",
    apiUrl: "https://api.staging.targetqa.com",
    defaultTimeout: TIMEOUTS.MEDIUM,
  },
  production: {
    baseUrl: "https://targetqa.com",
    apiUrl: "https://api.targetqa.com",
    defaultTimeout: TIMEOUTS.LONG,
  },
};

Utility Classes & Helper Functions

export class StringFormatter {
  static extractOrderId(text) {
    const match = text.match(/Order #(\d+)/);
    if (!match) throw new Error(Order ID not found in text: ${text});
    return match[1];
  }
}