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Variable hoisting is a process used by JavaScript engines to move the declarations of variables to the top of their respective scopes. In React, this process is similar to other JavaScript applications.

During variable hoisting in React, JavaScript engine moves all variable declarations to the top of their respective function or block scopes. This means that variables declared anywhere within a function or block scope are actually declared at the top of that scope, regardless of where the actual declaration appears.

For example, consider the following code:

function example() { console.log(message); var message = 'Hello World!'; }

In the above code, the variable message is declared after it is used in the console.log statement. However, during variable hoisting in React, the declaration of message will be moved to the top of the example function, before the console.log statement is executed. Therefore, when the code runs, message will be defined, and ‘undefined’ will be printed to the console.

Variable hoisting can have some unintended consequences if variables are not declared properly, so it is essential to declare variables at the top of their respective scopes to avoid these issues.