javascriptlexical-scope

lexical scope in Javascript issue

in the following code snippet, I defined "bob" first, but the output is "alice:1 hi alice", I don't know why?

let user = "";
function greet() {
  console.count(user);
  return `hi ${user}`;
}
user = "bob";
user = "alice";
console.log(greet());//alice:1 hi alice
Solution

  • The output is hi alice because, by the time greet() is executed, the variable is reassigned to alice.

    If you want the count to reflect the bob value, you should call greet() any time before its value is changed.

    Demo:

    let user = "";
function greet() {
  console.count(user);
  return `hi ${user}`;
}

user = "bob";
console.log(greet()); //hi bob

user = "alice";
console.log(greet()); //hi alice