JavaScript Strict Mode

JavaScript strict mode is a way to enable a stricter interpretation of JavaScript code. It helps catch common mistakes and prevents the use of certain error-prone features. When strict mode is enabled, the JavaScript interpreter enforces stricter rules for variable declarations, assignments, function definitions, and other aspects of the language.

To enable strict mode, you can add the following statement at the beginning of your JavaScript code or within a function:

"use strict";

Here are some key features and benefits of using strict mode:

1. Prevents the use of undeclared variables: In strict mode, assigning a value to an undeclared variable or using a variable without declaring it will result in a reference error. This helps catch potential typos and reduces the risk of accidentally creating global variables.
2. Disallows duplicate parameter names: In non-strict mode, declaring a function with duplicate parameter names would not cause an error. However, in strict mode, it will throw a syntax error, promoting cleaner and more maintainable code.
3. Blocks the use of deprecated features: Strict mode disables certain features and syntax that are considered deprecated or prone to errors, such as octal literals, implied global variables, and with statements. This encourages the use of more modern and reliable coding practices.
4. Enhances error handling: Strict mode provides more informative error messages by throwing exceptions for common mistakes, such as assignments to read-only properties or attempts to delete undeletable properties.

Using strict mode is generally recommended in modern JavaScript development as it helps catch and prevent common coding mistakes, promotes cleaner code, and aligns with the evolving standards of the language.