Search
 
SCRIPT & CODE EXAMPLE
 

JAVASCRIPT

closure in js

A closure gives you access to an outer function’s scope from an inner function
//example
function init() {
  var name = 'Mozilla'; // name is a local variable created by init
  function displayName() { // displayName() is the inner function, a closure
    alert(name); // use variable declared in the parent function
  }
  displayName();
}
init();
Comment

Closure ()

// 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.

Comment

closure in javascript

-->closure in javascript
//closure is the combination of function and the lexical enviornment in
//which the function is defined.closure give you access to the functions
//and variables outside the function.
function outer(){
  const outerData ="outer";
  function inner(){
    const innerData="inner";
    console.log(`${outerData} and{innerData}`);
  }
  inner();
}
outer();
Comment

closures in javascript

// A closure is a function having access to the parent scope, 
// even after the parent function has popped.

function greeting() {
    let message = 'Hi';

    function sayHi() {
        console.log(message);
    }

    return sayHi;
}
let hi = greeting();
hi(); // still can access the message variable
Comment

javascript closure

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
Comment

how javascript closures work?

function foo() {
  const secret = Math.trunc(Math.random() * 100)
  return function inner() {
    console.log(`The secret number is ${secret}.`)
  }
}
const f = foo() // `secret` is not directly accessible from outside `foo`
f() // The only way to retrieve `secret`, is to invoke `f`
 Run code snippet
Comment

closure in javascript

function makeFunc() {
  var name = 'Mozilla';
  function displayName() {
    alert(name);
  }
  return displayName;
}

var myFunc = makeFunc();
myFunc();
Comment

javascript closure

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.
Comment

js closure examples

function outer() {
  var counter = 0; // Backpack or Closure
  function incrementCounter() {
    return counter++;
  }
  return incrementCounter;
}

const count = outer();
count(); // 0
count(); // 1
count(); // 2
Comment

what is closure in javascript

function OuterFunction() {

    var outerVariable = 100;

    function InnerFunction() {
        alert(outerVariable);
    }

    return InnerFunction;
}
var innerFunc = OuterFunction();
Comment

es6 closures

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 */
Comment

JavaScript - Closures

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.
Comment

js closure

// global scope
var e = 10;
function sum(a){
  return function(b){
    return function(c){
      // outer functions scope
      return function(d){
        // local scope
        return a + b + c + d + e;
      }
    }
  }
}

console.log(sum(1)(2)(3)(4)); // log 20

// You can also write without anonymous functions:

// global scope
var e = 10;
function sum(a){
  return function sum2(b){
    return function sum3(c){
      // outer functions scope
      return function sum4(d){
        // local scope
        return a + b + c + d + e;
      }
    }
  }
}

var sum2 = sum(1);
var sum3 = sum2(2);
var sum4 = sum3(3);
var result = sum4(4);
console.log(result) //log 20
Comment

closure in javascript

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

console.log(counter.value()); // logs 0
counter.increment();
counter.increment();
console.log(counter.value()); // logs 2
counter.decrement();
console.log(counter.value()); // logs 1
Comment

what is a closure in javascript

// A Closure gives you access to an outer function's scope from an inner function.
// Example
function myNameIs(name) {
  return function(){
  	console.log('Hi my name is ' + name);
  }
}

let maxine = myNameIs('Maxine');
let amber = myNameIs('Amber');

maxine();
amber();
Comment

javascript closure

function numberGenerator() {
  // Local “free” variable that ends up within the closure
  var num = 1;
  function checkNumber() { 
    console.log(num);
  }
  num++;
  return checkNumber;
}

var number = numberGenerator();
number(); // 2
Comment

How do JavaScript closures work?

/*
A lexical environment is part of every execution context (stack frame) and is a map between identifiers (i.e. local variable names) and values.

Every function in JavaScript maintains a reference to its outer lexical environment. This reference is used to configure the execution context created when a function is invoked. 
This reference enables code inside the function to "see" variables declared outside the function, regardless of when and where the function is called.

If a function was called by a function, which in turn was called by another function, then a chain of references to outer lexical environments is created.
This chain is called the scope chain.

In the following code, inner forms a closure with the lexical environment of the execution context created when foo is invoked, closing over variable secret:
*/
function foo() {
  const secret = Math.trunc(Math.random() * 100)
  return function inner() {
    console.log(`The secret number is ${secret}.`)
  }
}
const f = foo() // `secret` is not directly accessible from outside `foo`
f() // The only way to retrieve `secret`, is to invoke `f`
 Run code snippet
Comment

Javascript Closure

function makeFunc() {
  var name = 'Mozilla';
  function displayName() {
    alert(name);
  }
  return displayName;
}

var myFunc = makeFunc();
myFunc();
Comment

closure in 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 
Comment

JavaScript Closures

// javascript closure example

// outer function
function greet() {
    // variable defined outside the inner function
    let name = 'John';
    // inner function
    function displayName() {

        // accessing name variable
        return 'Hi' + ' ' + name;
      
    }
    return displayName;
}

const g1 = greet();
console.log(g1); // returns the function definition
console.log(g1()); // returns the value
Comment

closure in javascript

// Explanation of closure
/* 1 */        function foo()
/* 2 */         {
/* 3 */             var b = 1;
/* 4 */             function inner(){
/* 5 */                 return b;
/* 6 */             }
/* 7 */             return inner;
/* 8 */         }
/* 9 */         var get_func_inner = foo();        
 
/* 10 */         console.log(get_func_inner());
/* 11 */         console.log(get_func_inner());
/* 12 */         console.log(get_func_inner());
Comment

Closures in 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
Comment

what is closure in javascript

document.getElementById('size-12').onclick = size12;
document.getElementById('size-14').onclick = size14;
document.getElementById('size-16').onclick = size16;
Comment

what is a closure in javascript

//Closures are the inner functions that are embedded in parent function
function getName(){
    // print name function is the closure since it is child function of getName
     function printName(){
         return 'Kevin'
     }
     // return our function definition
     return printName;
}

const checkNames = getName();
console.log(checkNames());
Comment

function - How do JavaScript closures work?

function createObject() {
  let x = 42;
  return {
    log() { console.log(x) },
    increment() { x++ },
    update(value) { x = value }
  }
}

const o = createObject()
o.increment()
o.log() // 43
o.update(5)
o.log() // 5
const p = createObject()
p.log() // 42
Comment

js closure

function aFunc(x){
  return () => console.log( x++ )
}
Comment

closure in javascript

A closure is a function bundeled together with its lexical scope
Comment

What is Closures in JavaScript

/*A closure is the combination of a function bundled together (enclosed) with references
to its surrounding state (the lexical environment). In other words, a closure gives you 
access to an outer function’s scope from an inner function. In JavaScript, closures are 
created every time a function is created, at function creation time.*/

function init() {
  var name = 'Mozilla'; // name is a local variable created by init
  function displayName() { // displayName() is the inner function, a closure
    alert(name); // use variable declared in the parent function
  }
  displayName();
}
init();
Comment

JavaScript Closures

function myFunction() {
  let a = 4;
  return a * a;
}
Comment

PREVIOUS NEXT
Code Example
Javascript :: get selected option from select javascript 
Javascript :: exit node 
Javascript :: change color in react 
Javascript :: babel compile files empty 
Javascript :: javascript this Inside Constructor Function 
Javascript :: opacity material ui 
Javascript :: Turn array items to matrix javascript 
Javascript :: delegate click in jquery 
Javascript :: what is useref in react 
Javascript :: clear input fild 
Javascript :: destructuring object 
Javascript :: show ad on facebook game 
Javascript :: how to use hammerjs in ionic 5 
Javascript :: .then message.delete 
Javascript :: ERROR TypeError: By.Subject is not a constructor 
Javascript :: reactjs sweet alert 
Javascript :: Vue Js pass parameters in computed properties 
Javascript :: Uncaught Error: [$injector:modulerr] http://errors.angularjs.org/1.4.6/$injector/modulerr?p0=myApp 
Javascript :: mongoose + populate 
Javascript :: javascript create object from key value pairs 
Javascript :: save byte as json string javascript 
Javascript :: find when webpage was last updated js 
Javascript :: jstree expend all node 
Javascript :: node js create or check directory 
Javascript :: json validator 
Javascript :: how to reload automaticaly in vue 
Javascript :: how to use cordova screen shot 
Javascript :: buscar una frase e un string js 
Javascript :: react-multi-carousel infinite loop causing issue 
Javascript :: js fit window to content 
ADD CONTENT
Topic
Content
Source link
Name
9+4 =