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So now did we have a understanding of how we can manage our files with the compiler.

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Let's dive into the compiler options because that's really interesting.

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This allows us to control how our types could code is compiled.

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So not only which files but also how the files which are getting compiled are treated by typescript.

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And there you see we have a bunch of options.

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Now you've got short explanations next to his options some explanations arguably are a bit cryptic.

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Others are quite clear and I will say that a lot of these options most of these options will not matter

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in most project so you'll not set all of these options.

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Not even close.

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You typically can ignore a lot of these options.

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Now we'll pick up on the important options here throughout this course because some options only make

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sense when we learn about a certain feature.

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And I want to dive into some options right now already though and for that let's go through that file

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from from top to bottom and see what we got there.

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And let's start with the target option as you see this actually is set by default.

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It's not commented out and what you do with this option is you tell typescript for which target javascript

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version you want to compile the code because what types could does is it does not just compile new features

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like to type annotations that don't exist in javascript to JavaScript code so it does not just take

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care that this here works.

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It also compiles the code to javascript that runs in a certain set of browsers and you basically define

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which browsers support the compiled code by setting the target the default target here in this project

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as you see the initial target which is getting set up is iOS 5 which means all types of code is compiled

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down and we can actually see that if I run TSC here to compile all my files we see an app Yes I'm using

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let and const but an app J.S. we see var and that happens because we've got a target of iOS 5 and in

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years 5 a world we don't have let and concept.

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So the good thing here is that we can use typescript to generate code that works in older browsers as

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well.

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But it's totally up to us if we want to do that.

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Maybe we don't want to do that with typescript because maybe we got some other built tool that will

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then take care about the javascript translation and therefore we don't want to have types could do that

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or maybe we want to ship code that only works in modern browsers because we know our app only will run

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in modern browsers and therefore alternative options can be seen here.

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If you delete the value and then here in V as code at least if you had control space to get the auto

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completion you see a bunch of suggestions and you'll see all available values here.

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Now over time this of course will change because we got new jobs come to worship it's released.

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You saw we set this two years five before.

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If you don't specify target at all then right now typescript compiles to e is free even so it supports

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an even older version but you can also go with iOS 6 which is more modern which for example supports

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constant let or take a even more recent version iOS 6 is the equivalent to iOS 2015 just for the record.

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So if we set this to iOS 6 for example and I rerun the T S C command after changing that he has conflict

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JS to file you will see that now in app chase we got led and const because now that is supported there.

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So that is up to you of course the more modern of a javascript word and you pick here the more concise

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your generated code is because typescript has to compile less and less code or it has to work around

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non existing features in less situations and therefore the compiled code typically is then more concise

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and shorter.

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So that's the target.

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What about the other options.