I have heard that in hoisting, the variable declaration is hoisted to top of the script or function. For example, I have a code snippet here:
console.log(sport); var sport = "cricket";
After hoisting, I am assuming the code will be like this:
var sport; console.log(sport); sport = "cricket";
If this is how hoisting works, who is actually doing the hoisting and moving the declaration to line 1?
Actually, nobody is moving the variable declaration code literally to the top. It is a perception based on how the code works.
So in the original code with just 2 lines, when the parser sees
var keyword next to
sport in line 2, it allocates a memory location for
sport and assign
undefined value. Note that only allocation happens in parsing step, initialization will not happen.
After parsing, when the actual execution starts, the interpreter is trying to print the value of
sport. Yes, there is one allocated during parsing step. It prints the value at that moment which is
undefined. Only when the interpreter jumps to second line, the value
"cricket" is assigned to
sport. This is how
console.log is able to use the variable
sport before it is declared in code.