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javascriptscopehoisting

JavaScript scope gets changed? Why does this happen?

The value of 'a' seems to lose global scope when the constructor a is called.

var a = 6;

function b() {
    a = 10;

    function a() {}
    console.log(a); //10
}
b();
console.log(a); //6
Solution

  • The order is interpreted as shown below due to variable hoisting. Note that as @ShadowCreeper correctly points out, function a(){} is actually creating a local variable a inside of function b which is hoisted as shown below.

    var a;
var b;

a = 6;
b = function() {
 var a;
 a = function(){};
 a = 10;
 console.log(a); //10
}
b();
console.log(a); //6