Does a function pickup latest changes?
중요도: 5
The function sayHi uses an external variable name. When the function runs, which value is it going to use?
let name = "John";
function sayHi() {
alert("Hi, " + name);
}
name = "Pete";
sayHi(); // what will it show: "John" or "Pete"?Such situations are common both in browser and server-side development. A function may be scheduled to execute later than it is created, for instance after a user action or a network request.
So, the question is: does it pick up the latest changes?
The answer is: Pete.
A function gets outer variables as they are now, it uses the most recent values.
Old variable values are not saved anywhere. When a function wants a variable, it takes the current value from its own Lexical Environment or the outer one.