Optional catch Binding

Summary: in this tutorial, you will learn how to use the optional catch binding in the try...catch statement.

Introduction to the optional catch binding

The try...catch statement is used to handle any errors that may occur. Generally, you place the code that may cause an error in the try block and the code that handles the error in the catch block, like this:

try {
    // code that may cause an error
} catch (error) {
    // code that handles the error
} 
Code language: JavaScript (javascript)

In the catch block, you can access the Error object that contains detailed information on the error.

In practice, you may want to use the try...catch statement to check if a feature is implemented in the web browser. If it isn’t, you want to fall back to a less desirable feature with broader support, for example:

try {
    // check if a feature is implemented
} catch (error) {
    // fall back to a less desirable feature
}Code language: JavaScript (javascript)

In this case, the error object is declared but never used.

ES2019 introduced the optional catch binding that allows you to omit the catch binding and its surrounding parentheses, like this:

try {

} catch {

}Code language: JavaScript (javascript)

Summary

• Since ES2019, you can omit the catch binding in the try...catch statement.