Comprehensive and Detailed Explanation From Exact Extract JavaScript knowledge:
This question tests understanding of let (block scope) and var (function scope) in JavaScript.
Initial declarations in the function:
let x = 1; // line 2
var y = 1; // line 3
Here:
x is declared with let, so it is block-scoped to the function body.
y is declared with var, so it is function-scoped to the entire function.
Inside the if (reassign) block (and since reassign is true, we enter it):
if (reassign) {
let x = 2; // line 6
var y = 2; // line 7
console.log(x); // line 8
console.log(y); // line 9
}
Detailed behavior:
let x = 2; on line 6 creates a new block-scoped variable x that exists only inside the if block. It does not change the outer x declared on line 2.
var y = 2; on line 7 declares y with var again, but var is function-scoped. This effectively reassigns the same y defined on line 3 for the entire function. After this line, y is 2 everywhere in the function.
Now, inside the if block:
console.log(x); (line 8) logs the inner block-scoped x, which is 2.
console.log(y); (line 9) logs y, which is the function-scoped y that was set to 2.
So the first two outputs are:
2
2
After the if block, execution continues:
console.log(x); // line 12
console.log(y); // line 13
Outside the if block:
The block-scoped let x = 2; no longer exists; it was only visible inside the if block.
The outer let x = 1; (line 2) is still in scope and has not been changed.
Thus:
console.log(x); (line 12) logs the outer x, which is still 1.
console.log(y); (line 13) logs y which, due to var y = 2; inside the if, is now 2 for the whole function.
Therefore, when myFunction(true) is called, the output in order is:
2 (inner x in if)
2 (function-scoped y after reassignment)
1 (outer x after if)
2 (function-scoped y remains 2)
This corresponds to:
JavaScript knowledge / study guide reference concepts:
let declarations and block scope
var declarations and function scope
Shadowing of variables with let inside a block
Re-declaration and reassignment of var within a function
Execution order of statements and console output
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