What is strict mode in JavaScript?

Strict mode is a feature in JavaScript that allows you to place your code in a “strict” operating context. When you use strict mode, the JavaScript interpreter will enforce stricter parsing and error handling rules, making it easier to write secure and reliable code.

Why use strict mode?

Strict mode helps prevent common programming mistakes and pitfalls by flagging certain code as errors that would otherwise be ignored by the interpreter. It can help you catch errors early in the development process and improve the overall robustness of your code.

Enabling strict mode

To enable strict mode in your JavaScript code, you simply add the following line at the beginning of your script:

"use strict";

Example

    
    "use strict";

    let x = 10;
    console.log(x); // Output: 10

    y = 20; // Error: Uncaught ReferenceError: y is not defined
    
    

Conclusion

Strict mode is a powerful tool that can help you write cleaner, more secure JavaScript code. By enabling strict mode in your scripts, you can catch errors early and improve the overall quality of your codebase.