What's wrong with the variable name in JS?

Question

var name = ['name1', 'name2', 'name2'];
console.log(name, name.length);
// name1,name2,name2 17

AND

var names = ['name1', 'name2', 'name2'];
console.log(names, names.length);
// (3) ["name1", "name2", "name2"] 3

What's wrong with the variable name in JS?

Its a reserved word. Check this: http://www.javascripter.net/faq/reserved.htm — Sunil, Apr 02 '18 at 05:45
[`name` is a property of the global `window`](https://developer.mozilla.org/en-US/docs/Web/API/Window/name). You cannot save anything but a string to it — Patrick Evans, Apr 02 '18 at 05:45
That's one reason why you should avoid to define own variables in the global scope. — t.niese, Apr 02 '18 at 05:48
Possible duplicate of [Using the variable "name" doesn't work with a JS object](https://stackoverflow.com/questions/10523701/using-the-variable-name-doesnt-work-with-a-js-object) — Sebastian Simon, Apr 02 '18 at 06:25

score 2 · Accepted Answer · answered Apr 02 '18 at 05:49

window.name Gets/sets the name of the window.

string = window.name;
window.name = string;

The name of the window is used primarily for setting targets for hyperlinks and forms. Windows do not need to have names.

It has also been used in some frameworks for providing cross-domain messaging (e.g., SessionVars and Dojo's dojox.io.windowName) as a more secure alternative to JSONP. Modern web applications hosting sensitive data should however not rely on window.name for cross-domain messaging but instead rather utilize the postMessage API.

Don't set the value to something unstring since its get method will call the toString method.

score 1 · Answer 2 · answered Apr 02 '18 at 05:49

This is because window.name is reserved. The type should be string. So when you declare name via var and assign an array, it will be implicitly converted to string.

You could try this code:

let name = ['name1', 'name2', 'name2']; console.log(name, name.length); // (3) ["name1", "name2", "name2"] 3

Because let variable will not be attached into window object.

You could refer this MDN link: https://developer.mozilla.org/en-US/docs/Web/API/Window/name.

What's wrong with the variable name in JS?

2 Answers2

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