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There's one last quick thing I want mentioned around functions so down here at the very bottom we're

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going to add in one last example here.

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Let's imagine for a second we have some object that describes today's weather.

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So maybe we call it forecast like so and maybe it's got a date to indicate today's date and the current

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weather outside.

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So maybe that will be a string that we'll call Sunny like so.

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Now let's try creating a function that's going to take that forecast and just log out the weather so

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to do so we could say something like const log weather and we're going to get some forecast object.

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We need to annotate the return type or singing the argument type right here.

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So to do so we would put in an object literal just like we saw previously with our variable annotation

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like what we saw right here so we would put in a call in and then curly braces and list out all the

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different properties that we would expect this forecast object to have.

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So maybe it will be a date that has a date type and a weather that has a string type thing in zoom out

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for just a second so you can see that whole line then after the list right there I'm only going to try

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to log out the current weather so there's not going to be anything I'm going to return.

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So Mark the return type is void and then put down my arrow where the function like so

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you're going to zoom back in.

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So now if we wanted to we could do a quick console log of forecast dot date and a console log of say

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forecast not weather like so and then just as a quick example down here we could try calling log weather

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with a forecast object and just to make the variables in here a little bit more clear maybe rather than

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calling this forecast it should be like today's weather.

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Maybe that makes a lot more sense.

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Now it's better all right now one little optimization we could do here would be to use a little bit

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of yes 2015 syntax and attempt to D structure the dates in weather properties out of the forecast variable

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right there.

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So in other words rather than having to refer to forecast start date and forecast out whether I want

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to just pull those two properties directly off inside the argument list if we were using normal.

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Yes 2015 syntax I'll put a quick example right here.

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We would write out something like this.

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We would say const log whether And then inside the argument list we would put a set of curly braces.

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And list the two properties we wanted to access.

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So in this case date and weather like so and then we could do a simple console log of date and of weather.

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So how do we use this kind of syntax right here.

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With a typescript annotation.

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All right I'm going to remove the yes 2015 and we're going to adjust the syntax in here just a little

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bit.

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So if we ever want to use these structuring along with an annotation all we have to do is replace the

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variable itself with the actual D structuring statement.

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So instead of forecast right there I'm going to replace it with a set of curly braces and I'll list

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out the different properties I want to pull out of that object.

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So the date and weather like cell and then I can adjust the body the function to be just state and whether

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so noticed that we did not tried to stick the annotation types along with the D structuring the D structuring

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portion and the annotation are always going to be two separate statements separated by that colon right

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there.

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So we're first going to do our D structuring and then we'll try to do with the actual annotation right

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after it.

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All right.

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So now we've seen that another quick pause right here and we'll move on to our last subject around annotations

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and inference.