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What is strict mode in JavaScript and why is it useful?

Asked on Jul 09, 2025

Answer

Strict mode in JavaScript is a way to opt into a restricted variant of JavaScript, which helps you write cleaner code by catching common coding errors and preventing the use of certain problematic features.

<!-- BEGIN COPY / PASTE -->
        "use strict";

        function exampleFunction() {
            // This will throw an error because x is not declared
            x = 3.14;
        }

        exampleFunction();
        <!-- END COPY / PASTE -->

Additional Comment:

Strict mode is enabled by placing "use strict"; at the beginning of a script or a function.
It helps in catching common mistakes such as assigning values to undeclared variables.
It prevents the use of certain JavaScript features that are considered problematic or deprecated.
Using strict mode can make your code more secure and robust by enforcing better coding practices.

✅ Answered with JavaScript best practices.

Ask any question about JavaScript here... and get an instant response.

What is strict mode in JavaScript and why is it useful?

Asked on Jul 09, 2025

Answer

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