CODEWITHSUNDEEP
javascript
Hello-World
Hello-World

Reputation: 9555

is this a closure in JavaScript as Im not sure?

Is this a closure in JavaScript?

var test = function(b){
    var a = 1;
    return function(b){
        a + b
    }
};
var c = test(2);

Upvotes: 0

Views: 139

Answers (2)

Uwe Günther
Uwe Günther

Reputation: 2971

var a; and parameter b of the outer function are part of the closure of the inner function. For detailed explanation of closures have a look in the FAQ

var test = function(b){ // <= param b is part of the closure of the inner function
    var a = 1;          // <= a is part of the closure of the inner function as well 
    return function(b){ // <= the inner function
        a + b           // <= here you are just add ind a and b together
                        //    return a + b; //would be more appropriate
    }
};
var c = test(2);

Upvotes: 0

Luke Channings
Luke Channings

Reputation: 1083

A closure is introduced then you define a function within test that returns local properties of the test function. an example of a closure would be here:

;(function() {

    var local = 123

    window.foo = function() {
        return local
    }
})()

What you're pretty close to in your example is currying, which involves a function that returns a function to take a second parameter. e.g:

function add(a) {
    return function(b) {
        return a + b;
    }
}

add(5)(6) // 11

Upvotes: 2

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