May I just share something that can help a bit more with this topic:
We can be tempted to look at var a = 2; as one statement, but the JavaScript Engine does not see it that way. It sees var a and a = 2 as two separate statements, the first one a compiler-phase task, and the second one an execution-phase task.
What this leads to is that all declarations in a scope, regardless of where they appear, are processed first before the code itself is executed. You can visualize this as declarations (variables and functions) being "moved" to the top of their respective scopes, which we call "hoisting".
Declarations themselves are hoisted, but assignments, even assignments of function expressions, are not hoisted.
Thanks for the write up Sai.
May I just share something that can help a bit more with this topic:
From You Don't Know JS
strongly recommend the whole series
Yeah sure I have also seen from other books(JavaScript for ninjas). Check out JavaScript weird parts good explanation about hoisting.