Strict mode in JavaScript programming
Strict mode in JavaScript Strict mode in JavaScript is a way to enforce stricter rules and restrictions when writing JavaScript code, which can help identify and prevent potential errors, security leaks, or performance issues. It is enabled by adding the following line at the beginning of a script or a function: "use strict"; When strict mode is enabled, the JavaScript interpreter will throw errors or disallow certain actions that are allowed in non-strict mode. Some examples of changes in strict mode include: 1. Variables must be declared with var , let , or const before being used, otherwise an error is thrown. Non-strict mode: x = 10; // No error, even though 'x' is not declared console.log(x); // 10 Strict mode: "use strict"; x = 10; // Error: x is not defined console.log(x); 2. Assigning a value to an undeclared variable, read-only property, or non-writable global variable will throw an error. Non-strict mode: NaN = "not a number"; /...