Python for loops create function-scoped variables, while transpiled JavaScript uses block-scoped let, causing reference errors when accessing loop variables post-loop.

Example:

def sum_range(n: int):
    total = 0
    for i in range(n):
        total = total + i
    return [total, i]  # Valid

function sum_range(n) {
    let total = 0;
    for (let i of Array.from({length: n}, (_, i) => i)) {
        total = (total + i);
    }
    return [total, i];  // ReferenceError
}

Proposed Fix:
Use var for loop variables accessed outside their loop, or implement static analysis to detect such cases.