“Zamknięcia w JavaScript” Kod odpowiedzi

Zamknięcie ()

// Closures
// In JavaScript, closure is one of the widely discussed and important concepts.
// A closure is a function that has access to the variable from another function’s scope which is accomplished by creating a function inside a function. As defined on MDN:
// “Closures are functions that refer to independent (free) variables. In other words, the function defined in the closure ‘remembers’ the environment in which it was created.”
// In JavaScript, closures are created every time a function is created, at function creation time. Most JavaScript developers use closure consciously or unconsciously — but knowing closure provides better control over the code when using them.
// Example:

function Spellname(name) {
var greet = "Hi, " + name + "!";
var sName = function() {
var welc = greet + " Good Morning!";
console.log(greet);
};
return sName;
}
var Myname = SpellName("Nishi");
Myname();  // Hi, Nishi. Good Morning!

// In the above example, the function sName() is closure; it has its own local scope (with variable welc) and also has access to the outer function’s scope. After the execution of Spellname(), the scope will not be destroyed and the function sName() will still have access to it.
Meandering Meerkat

Zamknięcie JavaScript

function makeAdder(x) {
  return function(y) {
    return x + y;
  };
}

var add5 = makeAdder(5);
var add10 = makeAdder(10);

console.log(add5(2));  // 7
console.log(add10(2)); // 12

//my words: what this code do is basically a nested function that will return
//its inner function (un-activated). So var add5 in line 7 activated the outer
//function with 5 as parameter which makes add5 is now the nameless function at
//line 2 that will return 5 + y;

//MDN words:
//add5 and add10 are both closures. They share the same function body
//definition, but store different lexical environments. In add5's lexical
//environment, x is 5, while in the lexical environment for add10, x is 10.
Graceful Grivet

Zamknięcia ES6

var makeCounter = function() {
  var privateCounter = 0;
  function changeBy(val) {
    privateCounter += val;
  }
  return {
    increment: function() {
      changeBy(1);
    },
    decrement: function() {
      changeBy(-1);
    },
    value: function() {
      return privateCounter;
    }
  }
};

var counter1 = makeCounter();
var counter2 = makeCounter();
alert(counter1.value()); /* Alerts 0 */
counter1.increment();
counter1.increment();
alert(counter1.value()); /* Alerts 2 */
counter1.decrement();
alert(counter1.value()); /* Alerts 1 */
alert(counter2.value()); /* Alerts 0 */
Kaotik

JavaScript - zamknięcia

function makeAdder(x) {
  return function(y) {
    return x + y;
  };
}

var add5 = makeAdder(5);
var add10 = makeAdder(10);

console.log(add5(2));  // 7
console.log(add10(2)); // 12

//=====
//add5 and add10 are both closures. 
//They share the same function body definition, but store different lexical environments. 
//In add5's lexical environment, x is 5, while in the lexical environment for add10, x is 10.
The Arborist

Zamknięcie w JavaScript

//Closures
Closures means a function bind together with its lexical environment
                           	OR
You can say a function along with its lexical scope bundle together forms
a closure
                            OR
In other words, a closure gives you access to an outer function's
scope from an inner function.
//Example
function x(){
  var a = 7;
  function y(){    //function y bind with its lexical enviroment
    console.log(a); 
  }
  a = 100;
  return y;
}
var z = x();
console.log(z) //Output is 100
Mubashar

Zamknięcia w JavaScript

let counter = (function() {
    let i = 0; // private property

    return {   // public methods
        get: function() {
            alert(i);
        },
        set: function(value) {
            i = value;
        },
        increment: function() {
            alert(++i);
        }
    };
})(); // module

counter.get();      // shows 0
counter.set(6);
counter.increment(); // shows 7
counter.increment(); // shows 8
Ali Salman

Odpowiedzi podobne do “Zamknięcia w JavaScript”

Pytania podobne do “Zamknięcia w JavaScript”

Więcej pokrewnych odpowiedzi na “Zamknięcia w JavaScript” w JavaScript

Przeglądaj popularne odpowiedzi na kod według języka

Przeglądaj inne języki kodu

Shell/Bash
C#
C++
C
CSS
HTML
Java
JavaScript
Objective-C
PHP
Python
Sql
Swift
Ruby
TypeScript
Go
Kotlin
Assembly
R
VBA
Scala
Rust
Dart
Elixir
Clojure
Haskell
Matlab
Erlang
Cobol
Fortran
Scheme
Perl
Groovy
Lua
Julia
Delphi
Abap
Lisp
Prolog
Pascal
ActionScript
Basic
Solidity
PowerShell
GDScript
Excel