What will be the output of the following code: console.log(x); var x = 10;

In the provided code snippet, the output of console.log(x); var x = 10; will indeed be undefined. This behavior is a result of JavaScript's variable hoisting mechanism.

When the JavaScript engine processes the code, it first hoists the declaration of the variable x, which means it acknowledges that x exists before it reaches the line where it is logged to the console. However, the assignment of 10 to x occurs only after the console.log call. So, at the time of the console.log execution, x has been declared but not yet initialized, leading it to have the value undefined.

To summarize, JavaScript hoisting allows variable declarations to be lifted to the top of their containing function or scope, so even though var x = 10; appears later, x is recognized as a declared variable when console.log(x); is executed, resulting in an output of undefined.