Knowledge of databases and working with APIs.

For a front-end developer, it is important to understand the basics of working with databases and APIs to efficiently retrieve and display data.

Databases:

• Knowledge of main types of databases: relational (e.g., PostgreSQL, MySQL) and non-relational (e.g., MongoDB).
• Understanding CRUD operations (Create, Read, Update, Delete).
• Basics of SQL queries for data selection and filtering.

Working with APIs:

• Understanding REST architecture and main HTTP methods (GET, POST, PUT, DELETE).
• Ability to send requests to APIs using fetch, axios, or other libraries.
• Handling API responses, including working with JSON.
• Error handling and HTTP status codes.

Example of an API request using fetch:

fetch('https://api.example.com/users')
  .then(response => {
    if (!response.ok) {
      throw new Error('Network error');
    }
    return response.json();
  })
  .then(data => {
    console.log(data); // processing received data
  })
  .catch(error => {
    console.error('Error:', error);
  });