What are the Benefits of Using the use strict Directive in JavaScript ?

The "use strict" directive enables strict mode in JavaScript, which provides several benefits:

• Strict mode eliminates some JavaScript silent errors by changing them to throw errors.
• Strict mode fixes mistakes that make it difficult for JavaScript engines to perform optimizations: strict mode code can sometimes be made to run faster than identical code that’s not strict mode.
• Strict mode prohibits some syntax likely to be defined in future versions of ECMAScript.
• It prevents, or throws errors, when relatively “unsafe” actions are taken (such as gaining access to the global object).
• It disables features that are confusing or poorly thought out.
• Strict mode makes it easier to write “secure” JavaScript.

Example: Here, the code is in strict mode due to the presence of the "use strict" directive at the beginning. When the variable x is assigned a value without being declared first, a ReferenceError is thrown, indicating that x is not defined. Strict mode helps catch such errors at runtime, making the code more robust.

Javascript

"use strict";

x = 10; // Throws a ReferenceError: x is not defined

Output:

// Throws a ReferenceError: x is not defined