Exploring the concept of closure led me to conduct some experiments, and a specific problem caught my attention.
Upon running the following code:
var hello;
hello = 'abc';
test();
function test() {
console.log(hello);
}Output: 'abc'
However, upon adding another variable declaration within the function, the output changes:
var hello;
hello = 'abc';
test();
function test() {
console.log(hello);
var hello = 'xyz';
}Output: undefined
I find it puzzling why this behavior occurs. When the test() function is executed, it should log the global variable 'hello' before any declaration inside the test() function has been processed. Therefore, it seems unexpected that the result is undefined.
Any insights would be greatly appreciated.