var i = 100;
function addI(){
var i = 0;
return function(){
iPP;
console.log(i);
}
}
addI()(); // 1
addI()(); // 1
var c = addI();
c(); // 1
c(); // 2
encountered this interview question today, ask for the popularization of science.
Why is the addI () () all 1 (understandably), while the c () () execution I is incremented?
is a bit shameful and unsure-- I understand that: add () () simply executes the add method, and when the add method is referenced to the c object, the c object always exists (lively referencing the method in the), add method forms a closure (at this time the add method referenced by the c object has formed a closure). On the first call, the I object in the add method is assigned a value of 0, and when the anonymous function is executed, the internal I has no value, find the external I, and PP. On the second call, the add method declares an I object again, but the I in the internal anonymous function at this time retains the value of the last call. So directly in the result of the last call iPP. I don't know whether it is correct
addI () = addI () / / false
each run produces a different result function, each referring to the I value in its own closure.
if the same function runs, it will continue to modify the I value in the closure to which the function belongs.
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