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As you learned, Javascript is a hosted language, that means Javascript itself,

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the definition of the language can be implemented in different environments.

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All you need in the end is a Javascript engine that parses the code and executes it in the end

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and one very common environment of course is the browser. Browsers have their own Javascript engines,

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like the V8 engine in the case of Chrome

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and this in the end hosts and executes the Javascript code therefore. Now togetger with the browser

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APIs you learned about, like the DOM or the browser storage or the fetch API and so on,

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you got tools to build rich client-side applications where you utilize the language and all its key features

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and keywords and so on

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combined with the browser APIs to provide the user experience you want to provide, all of that then

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runs in the browser, so directly where your users are but of course nothing speaks against taking Javascript

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and executing it somewhere else.

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We can do that,

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we can execute Javascript anywhere else we want by simply taking the Javascript engine and taking it

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out of the browser basically and that's it.

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We can then add our own APIs if we want to,

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so not APIs to work with the DOM for example because if the Javascript engine, if the environment is

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detached from the web page, there is no DOM right,

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there is no HTML code which we could parse if we run Javascript somewhere else but instead we might

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want to add new APIs, APIs which don't exist in the browser, for example to work with the local file

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system which is not possible in the browser due to security reasons

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and that's exactly what Node.js does. Node.js is essentially the extracted V8 engine Chrome offers enriched

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by extra APIs, so its that engine you know from the browser

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but basically instead of the browser APIs, it has access to other APIs and it runs outside of the browser,

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this is Node.js

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and of course this also implies that what you learned about Javascript still is relevant,

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just the browser specific parts like the DOM or the browser storage of course are not important when we

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work with Javascript outside of the browser.

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So let's now have a look at Node.js.