Salesforce JavaScript Developer Practice Exam

What will be the console output when redefining a variable with var?

1. 8

2. 10

3. SyntaxError

4. ReferenceError

The correct answer is: 10

When a variable is redefined using the var keyword in JavaScript, it does not result in an error, and the variable will simply be updated with the new value. The var keyword allows for function-scoped or globally-scoped variables, and it permits redeclaring the same variable multiple times within the same scope without throwing any exceptions. In this scenario, if the variable was initially defined with a value of 10 and is then redefined with a new value, the console will output the most recent value assigned to that variable. Therefore, if the final assignment is to set the variable to 10, then the console will output 10. Variables declared with var do not have the same restrictions as let or const, which can lead to different behaviors regarding redeclaration and scope. This flexibility makes using var convenient, especially in scenarios where you want to allow the variable to change over time within its scope. In summary, when you redefine a variable declared with var, the latest value is what gets reflected when you log the variable to the console, which in this case is 10.