JavaScript

Stopping a JavaScript Function When a Certain Condition is Met

In most programming languages, stopping a function is very useful when we need to quit quickly in the middle of the function or when a certain condition is fulfilled. Also, it assists in situations where you only wish to employ a portion of the function’s capability in the application. For that purpose, JavaScript provides various ways including the “return” statement and the “try/catch” statement to stop or quit the function.

This write-up will explain various methods for stopping a JavaScript function.

How Do I Stop a Function When a Condition is Satisfied?

To stop a function when a particular criterion is fulfilled, the “try/catch” or “break” keyword can be used. Furthermore, you can also utilize the “return” statement that will retrieve a certain value according to the specified condition.

For practical implications, check out the stated methods one by one.

Method 1: Using the “try/catch” Statement
In this stated method, define a function with a particular name. Then, use the “try/catch” method. Furthermore, check the condition if the number is greater than “5” to show the value as “Number is greater than 5” or catch the error message:

function check(number) {
 try {
  if (number > 5) throw "Number is greater than 5";
  }
 catch (error) {
  console.log('Error:',error)
 }
};

Call the “check()” function and pass the number as the argument to the defined function:

check(15);

It can be observed that the passed number is greater than 5:

Method 2: Using “break” Statement
To stop a function via a break statement, users must wrap the function’s code within a loop, and then use the break statement to exit the loop when the certain condition is met. Here’s an example that illustrates the use of the break statement regarding stopping a function in JavaScript:

function stopFunc() {
    for (let i =0; i < 20; i+=2) {
        if (i == 10) {
      break;
      }
    console.log(i);
    }
console.log("Function terminated");
}

stopFunc();

It can be observed that the given function stopped when the value of “i” becomes 10:

Method 3: Using “return” Statement
The “return” statement is used for returning a particular value of a function. For instance, the return statement is utilized to output a certain value against a specified condition and quit the function. In this particular example, a function is defined as “stopFunc()” with two parameters. If the criteria are fulfilled then, it will return “0”. Otherwise, the result will be shown as “true”:

function stopFunc(x) {
 if (x>10) {
  return("true")
 }

Now, invoke the “console.log()” method and call the defined function as the argument. Furthermore, pass the numbers as the parameter to the function:

console.log(stopFunc(23));

It can be seen that the output of the stated code is mentioned below:

That’s all about stopping the JavaScript function when a certain condition is met.

Conclusion

To stop a JavaScript function, the “return” statement, “break” statement, and try-catch can be used. To stop a function via a break statement, users must wrap the function’s code within a loop, and then utilize the break statement to quit/jump out of the loop when the certain condition is fulfilled. This post stated the method for stopping the function when a condition is fulfilled.

About the author

Hafsa Javed