Vigezo vya Kitaifa na Vigezo vya Kazi katika JavaScript

Tuchukulie tuna kazi inayokubali kigezo cha nambari:

javascriptfunction func(localNum) {
  console.log(localNum);
}

Tuchukulie nje ya kazi kuna kigezo num:

javascriptfunction func(localNum) {
  console.log(localNum);
}

let num = 1; // kigezo cha nje cha kitaifa

Wacha tuite kazi yetu, tukiipitishia kigezo num:

javascriptfunction func(localNum) {
  console.log(localNum);
}

let num = 1;
func(num); // tunaita kazi na kigezo, itatoa 1

Itafanyika kuwa ndani ya kazi itapatikana kama kigezo localNum (kigezo cha kazi), na pia kigezo num (kama kigezo cha nje):

javascriptfunction func(localNum) {
  console.log(num); // itatoa 1
  console.log(localNum); // itatoa 1
}

let num = 1;
func(num);

Kigezo localNum cenyewe kitakuwa kigezo cha ndani cha kazi na hakitapatikana kutoka nje:

javascriptfunction func(localNum) {
  
}

let num = 1;
func(num); // tunaita kazi na kigezo
console.log(localNum); // itatoa hitilafu

Kwa kuwa kigezo localNum - cha ndani, hakuna mabadiliko yoyote na yake yatakayobadilisha kitu nje:

javascriptfunction func(localNum) {
  localNum = 2; // haibadilishi chochote nje
}

let num = 1;
func(num);

Lakini ikiwa tubadilishe ndani kigezo num (cha kitaifa), basi mabadiliko yataonekana na nje:

javascriptfunction func(localNum) {
  num = 2;
}

let num = 1;
func(num);
console.log(num); // itatoa 2

Hata hivyo, ikiwa ndani ya kazi tutatangaza kigezo num kupitia let, basi tutaunda kwa njia hii kigezo cha ndani num, kisichoathiri kigezo cha nje:

javascriptfunction func(localNum) {
  let num = 2; // tutatangaze kupitia let
}

let num = 1;
func(num);
console.log(num); // itatoa 1 - hakuna kitu kilibadilika

javascriptfunction func(localNum) {
  console.log(localNum);
}

func(1);

javascriptfunction func(localNum) {
  console.log(localNum);
}

let num = 1;
func(num);

javascriptfunction func(localNum) {
  console.log(localNum);
}

let num = 1;
func(num);
num = 2;

javascriptlet num = 1;

function func(localNum) {
  console.log(localNum);
}

num = 2;
func(num);

javascriptfunction func(localNum) {
  localNum = 2;
}

let num = 1;
func(num);
console.log(num);

javascriptfunction func(localNum) {
  num = 2;
}

let num = 1;
func(num);
console.log(num);

javascriptfunction func(localNum) {
  let num = 2;
}

let num = 1;
func(num);
console.log(num);