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Hey, welcome back in this lesson, we're going to be looking at the switch statement and what the switch

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statement does that evaluates an expression so matching the expressions value to the case clauses and

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then executes the statements associated with that case.

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So let's check it out and show you some examples of that.

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So I've set up an input area as well as a button.

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So we're just ask what time is it?

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And then we've got a button.

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So let's make these interactive these fields so we'll select the input area as well as the button.

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So button document using query selector.

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Let's select the button element so we only have the one.

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So just select that first one and I'll just do another one for answer and do document and query selector

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and we'll select the input.

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And as we only have one input, it's going to be relatively easy to pick these up.

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So adding an event listener to the button so that we're going to be listening for is a click.

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Whenever it gets clicked, it's going to run a function.

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And within this function, what do we want to happen?

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We want to ask the question, so what time is that?

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And we're going to do an evaluation on the switch statements.

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We'll have the switch statement here and here.

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And for now, we'll just output whatever the value of the answer and whatever the value is that's associated

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with the answer.

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So if there is no value for the answer, then we're not going to try to provide a solution for it.

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So we need to make sure that we do have a value within the answer.

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So let's try that and put in a value.

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And so now we get the value output there.

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So we want to make sure that whatever we're outputting, whatever responses in there, that this is

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going to be an actual number that we can use.

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So let's check out then let's grab that value and we're going to check to see the type that it is.

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So will console log out type of and this will tell us the data type, so by default, within the input,

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it's going to be a string value.

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So even though we've got numbers in there, it's still going to be returned back as a string.

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So we want to do is we actually want to convert it into a number.

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So let's set up a variable and set up a brand new variable and using a number, let's convert the answer

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value into a number and then we'll also get the type of four Antz.

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So the original is always going to be a string.

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So want to check to see what we're returning back and if it's a number and what type it is.

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So let's try that one more time.

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So we've got some letters.

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So it's a string, the original ones, a string and now it's been turned into a number and string and

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numbers.

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So with no we're always turning it into a number, but it doesn't necessarily mean that it is an actual

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value of a number.

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So if we cancel out the value of ants, if it's a string, then it's actually going to be returning

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back as an end.

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So if we've got a string value, it's turned back as an and and if we have a number that's going to

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still return it back as a numbers.

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So the NUM conversion is going to either check to see if it's a number and if it's not a number, then

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turn it back as not.

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So that is a variable that we can use and value representing, not a number.

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So if none is equal to and then that means that console log not a number and just duplicate that and

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else and move that in there.

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So it's aligned.

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I'll get rid of that extra line and I'll just put.

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OK, so let's check to see what gets returned back here.

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So forty four is OK whereas.

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What we're returning back, so this is being treated as a no, Sanon is being returned back as a no.

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So we're still returning back.

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OK, so it's not checking to see if it's value of nine.

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It's just checking to see if it's not a number.

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So let's update this with no and we'll just check to see if now it's going to return that and it's still

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returning back.

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OK, so this is a problem using the no method.

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So let's use the pass integer and it's going to return it back as no value and that will give us different

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values there.

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So let's update this stuff.

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So now we're using ETR and it's been returned back as not a number.

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And now we've got a number and it's been returned back as a number of value.

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So both pass integer and no, they both are converting it into a number of the difference between pass

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integer is that if you have value and then if you have some numbers, it's going to return it back up

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to where it sees the end of the number, whereas number is going to return that back separately.

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And if we do, instead of parse integer, if we use no method in order to do the conversion and we do

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two, it's going to just return it back as.

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Not a number, so it's not going to take any of the additional values, whereas Pass Integer is going

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to return it back as two, so there's a difference there.

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And depending on what you want to use, you can use either the pass integer or the number.

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So let's use the pass integer in case that there are some other values that are entered in there.

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So we want to get any of the value, the number of values out of that.

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So now that we've got all of that and we're still not able to check to see if this is an actual number,

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if it's a valid number value.

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So let's take a number and we'll see if this works as we do need to have a number of value for the switch

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statement.

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So let's add in a number and it's coming back, not a number and it's coming back that this is OK.

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So that is OK.

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So we need to negate this and then we should be good to make sure that we're checking to see if not

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a number.

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And now we are getting a number.

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So it is OK, stay tuned for part number two.

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Coming up, where we're going to look at switch statements.