11 - Return statements (Javascript)

Understanding Return Statements in JavaScript

Return statements are a fundamental concept in JavaScript that allows you to control the flow of your code and produce values from functions. In JavaScript, a return statement specifies the value that a function will return as its output. This returned value can then be used in further operations or stored in variables. In this discussion, we’ll explore the importance of return statements and how they can be used effectively in JavaScript functions.

What Is a Return Statement?

A return statement is a built-in JavaScript statement that defines the output of a function. It is used to terminate the execution of a function and send a value back to the point in the code where the function was called. This returned value can be a specific data type or even an expression, making it a versatile tool for functions to produce results.

Using Return Statements

Return statements are placed within a function to indicate what the function should return when it completes its execution. Here’s the basic structure of a return statement within a function:


function add(a, b) {
    return a + b;
}

In this example, the add function takes two parameters, a and b, and returns their sum using the return statement. When you call this function with specific arguments, it returns the result of the addition.

Returning Values from Functions

Return statements allow functions to provide output or results to the code that called them. You can use these returned values in various ways, such as assigning them to variables, using them in conditional statements, or passing them as arguments to other functions.

Example of returning a value from a function:


function square(x) {
    return x * x;
}

let result = square(5);
console.log("The square of 5 is " + result);

In this case, the square function returns the square of the input value x, which is then assigned to the result variable. The value of result is used in the subsequent console.log statement to display the result.

Early Termination with Return

Return statements are not limited to just returning values; they also allow for early termination of a function’s execution. When a return statement is encountered, the function exits immediately, skipping any subsequent code within the function.

Example of early termination with return:


function isPositive(number) {
    if (number > 0) {
        return true;
    }
    return false; // This line is not reached if 'number' is positive
}

In this example, if the number is greater than zero, the return statement is executed, and the function exits. If the number is not positive, the function proceeds to the next line, which returns false.

Multiple Return Statements

Functions can have multiple return statements to provide different outputs based on different conditions. Each return statement can return a different value or result, allowing the function to handle various cases.

Example of multiple return statements:


function checkNumber(number) {
    if (number > 0) {
        return "Positive";
    }
    if (number < 0) {
        return "Negative";
    }
    return "Zero";
}

In this example, the checkNumber function has three return statements to return different values based on whether the input number is positive, negative, or zero. The appropriate return statement is executed depending on the condition.

Conclusion

Return statements are a crucial aspect of JavaScript functions, allowing you to control the flow of your code and produce meaningful results from functions. Understanding how to use return statements effectively is essential for writing functions that provide valuable output and contribute to the overall functionality of your JavaScript programs.

11 – Return statements (Javascript)