**Functions** are reusable blocks of code that can be called at different parts of your program. They help modularize and organize your code, making it easier to understand and maintain. ## <br>How to define a function For this post I will use Javascript ```js function functionName(param1, param2) { // code block return result; } ``` + `functionName`: the name of the function. + `param1`, `param2`: parameters the function can receive. + `return`: the keyword used to return a value from the function. See below for a small example ```js function add(a, b) { return a + b; } let result = add(5, 3); // 8 ``` ## <br>Methods in JavaScript Methods are functions associated with objects. They are used to manipulate the object's data or to perform operations related to it. **How to define a method** ```js let object = { property: value, method: function() { // code block } }; ``` **Example**: ```js let car = { make: "Toyota", model: "Corolla", year: 2020, start: function() { console.log("The car is started."); } }; car.start(); // "The car is started." ``` ## <br>Best Practices for Coding in JavaScript 1. **Meaningful Names**: Use variable, function, and method names that are descriptive and clear. ```js let userAge = 25; // Clear and descriptive ``` 2. **Avoid Code Duplication**: Use functions to encapsulate reusable code. ```js function calculateRectangleArea(width, height) { return width * height; } ``` 3. **Keep Functions Short and Focused**: Functions should do one thing and do it well. ```js function calculateAverage(numbers) { let sum = numbers.reduce((a, b) => a + b, 0); return sum / numbers.length; } ``` 4. **Use** `const` **and** `let` **Instead** of `var`: Use `const` for constants and `let` for variables that may change. Avoid `var` to prevent scope issues. ```js const PI = 3.14159; let age = 30; ``` 5. **Comments**: Write comments to explain code that isn’t immediately obvious. ```js // Calculates the area of a circle function calculateCircleArea(radius) { return PI * radius * radius; } ``` 6. **Avoid Deeply Nested Functions**: Try to avoid too many levels of nested functions, as it can make the code harder to read and maintain. 7. **Consistency in Style**: Maintain consistent coding style, such as using camelCase for variable and function names. ```js let fullName = "John Doe"; // camelCase ``` 8. **Handle Exceptions**: Use `try...catch` to handle errors and prevent your program from crashing unexpectedly. ```js try { // code that may throw an error } catch (error) { console.error(error); } ``` These concepts and practices will help you write cleaner, more efficient, and easier-to-maintain code.