CODEWITHSUNDEEP
javascript
Karambit
Karambit

Reputation: 356

weird variable hoisting in javascript

so we know that variables declared with the var keyword are hoisted and if we try to access their value before they have been initialized we get undefined. However, In the code below logging the name variable logs the function and not undefined why ?

console.log(name);
console.log(lol);

var name = function(args = "Hello World"){
    console.log(args)
}

var lol = function(args = "Hello world") {
    console.log(args)
}

the output is 

function(args = "Hello World"){
    console.log(args)
}

and

main.js:57 undefined

why isnt name variable undefined ?

Upvotes: 0

Views: 79

Answers (3)

Ralph Ritoch
Ralph Ritoch

Reputation: 3440

The window which is the root scope already has a name property. Try the following and look at the output in your console. If you click the link the page that opens has MyWin as the output for name.

HTML (test.html) 

<head>
    <title>test</title>
</head>

<body>
    <a href="test.html" target="MyWin">Click me!</a>
    <script src="test.js"></script>
</body>

</html>

Javascript (test.js)

console.log("name", name);
console.log("notname", notname);
console.log("lol", lol);


var notname = function (args = "Hello World") {
    console.log(args)
}

var lol = function (args = "Hello world") {
    console.log(args)
}

Upvotes: 2

Himanshu Pandey
Himanshu Pandey

Reputation: 708

I think you should logging like that why you confused.

console.log(name);
console.log(lol);

var name = function(args = "Hello World"){
    console.log(args)
}

var lol = function(args = "Hello world") {
    console.log(args)
}

console.log(name);
console.log(lol);

Upvotes: 0

codeandcloud
codeandcloud

Reputation: 55250

Consider the code

console.log(test);

var test = function(args = "Hello World"){
    console.log(args)
}

This will return undefined because only declarations are hoisted. That is, your code after hoisting will be

var test;
console.log(test);

test = function(args = "Hello World"){
    console.log(args)
}

Upvotes: 0

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