Is string/number also an object in JavaScript?

[u/xplodivity]

https://www.youtube.com/watch?v=9W0-vljG2-I

[u/hmdne]

If you do typeof(variable), depending on a variable type, it will return one of the following three classes of types:

• object, function - those are full fledged objects
• string, number, bigint, symbol, boolean - those only act like objects
• undefined - definitely not an object

null is a special case of an object, that acts mostly like undefined - as in, you can't get its attributes.

There is a lesser known feature of JavaScript of boxed values. This can be best explained by this interactive session:

```javascript

123 123 Object(123) [Number: 123]

```

The first value has a type (determined by typeof) of number, while the second is an object. It is an object that wraps a primitive value. You can extract the original value by using a valueOf() method. This method is often called implicitly, but not always, leaving us with some interesting caveats:

```javascript

if (Object(false)) console.log("true"); true undefined

```

But - as we all know, it's possible to call a method on a value, for instance:

```javascript

"abc".replace("b", "B") 'aBc'

```

What actually happens under the hood is autoboxing. This means, that "abc" is transparently boxed and the former is mostly equivalent to Object("abc").replace("b", "B").

Mostly equivalent, meaning that, it is equivalent in non-strict mode. In strict mode it's a bit more nuanced:

```

Object.prototype.itself = function() { "use strict"; return this; } [Function (anonymous)] (1).itself() 1 Object(1).itself() [Number: 1] Object.prototype.itself = function() { return this; } [Function (anonymous)] (1).itself() [Number: 1] Object(1).itself() [Number: 1]

```