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We have briefly in the earlier lessons, looked at some data types, and we're going to look at this

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in more detail in this lesson, that script standard, there's several different standard data types.

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So there are booleans.

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So we know those are either true or false.

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There's numbers.

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So those can be written with or without a decimal place.

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There's strings so they can be written with a single or double quotes.

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There's also NUL.

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So this is explicitly nulls.

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So there's nothing.

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And by default, when you declare a variable and if you haven't assign any value to it, then it's comes

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back as undefined and there's also symbol and symbol value.

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So it represents a unique identifier symbol.

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It's new in ECMAScript 2015 and it's data type whose instances are unique and immutable and everything

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else or almost everything else in JavaScript is an object type.

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You can also, with JavaScript, convert between different types.

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And we have seen this as well, where when we've got we can start out with a boolean or we can start

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it with the string and then when we assign a number to it, the data type becomes a number.

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So there is flexibility with JavaScript, but you can also force the different data types and the type

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conversion so you can convert a number to a string by wrapping it with the string methods typing in

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string and then the rounded brackets and then using the value or the variable.

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That's a number.

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And that can turn that into a string.

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And there's also arrays that can be turned into strings and there's more on arrays coming in the upcoming

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lessons.

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You can also use the dot to string methods are changing the one value together with another one, and

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that's going to turn it into a string so you can convert it into a number so you can force a string.

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And as you can see, the 10 has the quotes around it.

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So this is a number.

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You can also turn a boolean into a number.

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And if you try to turn something that is not a number, could never be a number into a number, you're

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going to get this.

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And again, so that stands for not a number.

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And we can all log these out into the console and try these and take a closer look at this.

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There's also type core coersion, which is converted by JavaScript.

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If we add a number to a number or if we had a string or something, that's not a number to a number,

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then if it can't be converted into a number, then it's going to automatically turn it into a string.

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So JavaScript tries to do some of the thinking for us and trying to convert the different values into

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the appropriate data type.

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And more often than not, this is a common issue when you have values that you think are numbers and

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you try to add them together and it turns out to do ten plus five and it ends up with something like

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one or five instead of 15.

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So we find that when we are doing data types, sometimes it's a good idea to force the value and make

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sure that it is the data type that we are trying to work with.

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You can also have some fun with the different data types.

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So one of the JavaScript quirks is that the data types are dynamic.

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So this means that JavaScript does try to convert it and we can of course, convert it with the number

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or string methods which allow us to force various data types.

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And as you can see in these examples.

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So if we do hello plus world, we end up with a string hello world.

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If we do five, which is a string plus a number string, we're going to end up with fifty five, ten

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minus five.

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We're not going to be able to subtract it, but it is going to convert this into a number and then we're

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going to end up with five.

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So there are a bunch of little strange things that do happen with JavaScript and you can try these out

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in the console in order to get more familiar with it syntax to use in order to get data types.

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So if we do, type of that will return the different data types.

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I'll show you how to do that in the console and then also output that information into the console.

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So if we have a five and we want to find out what data type it is, we want to output that value and

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see what data type the five is.

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So opening up our browser and we can see that we have a value that's a string.

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So if we have a string and if we add a five to it, we end up with the 55 string.

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If we have a 10 and we subtract a five to it, we end up with a five.

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So that's one of the weird quirks of JavaScript, is that this one, although they both started out

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as strings, when you subtract it, then it automatically thinks, OK, well, because we can't subtract

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one string from another.

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So then it automatically tries to convert this first one to a number and this is what happens.

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So this is what I meant by there are some weird quirks that will happen with JavaScript.

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So if we take something like hello and if we subtract world from it, we're going to see that.

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And and so that's not a number because of course, we can't subtract words one from another.

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So that's a little bit confusing.

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And JavaScript tries to address it and adjust it.

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And if it can't, then it simply returns back that end.

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And you can also set up a variable.

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So if we set up a variable and if we set up a variable of a as five.

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Type of a you're going to see that it gets returned back a string type of and if we have a value that

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is a number, you can see that it gets returned back as a number.

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And also there's type of and this one is going to be a boolean and it's going to know it's a boolean

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because booleans, again, are either true or false.

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So we know that those are booleans.

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If you do type of null, it gets return back as an object type of undefined and that just gets returned

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back as undefined because undefined is its own data type.

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It is good to become familiar with them.

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And as we saw with a.

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So we've got a is currently string value and you can convert it to a number, convert it into a number

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so we can take the value of string and we can turn it into a number.

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So when it's blue it's being returned back as a number, a value of one hundred.

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So this is clearly a number and we can convert it into a string using the two string method string as

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well.

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So there are actually two ways to convert it into a string.

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So those are the two examples of how we can convert it.

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And then if you ever want to find out the type, all you have to do is type in.

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Type of.

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So let's go back to our challenge.

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And the challenge is to create a string convert to different data types and then get the data type of

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the variable and output that type to the console solution.

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We're going to create a number, give it a string value of five, then take that string and convert

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it into a number, outputted as a number, and then check the data type of the myname.

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So make sure that it has converted.

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So go ahead and try this out in your editor.

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You can pause the video and I'll show you the solution.

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Open up the editor and let's set up myname and this can be any number that we want.

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So A set my number to one hundred and then we'll take and what we'll do first will use console log and

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will output the type of my num so that you can see that it actually is being converted.

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So when we refresh we see the type as a string and convert it.

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So there is the number and we're taking the variable and we're converting it through.

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It's being returned back as a number.

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And if we log out the value of my NUM, you can see as well Chrom is outputting it as a number since

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it's blue and wait, hold everything before we conclude, I have another challenge for you.

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So this is a bonus challenge.

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Did you get a chance to try some of that in your console where you're adding maybe two strings together,

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maybe two numbers together and maybe a string and a number and see what happens?

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So try that out as well and output the value of five to ten and then fix A plus B to equal 15.

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And remember converting those two numbers in order to add them together.

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So the solution for this one setting up a as five, setting up B as ten, and then we want to do is

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add those together in the console, but we want to have a value of 50 instead.

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Right now we're getting five, ten.

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So let's fix that.

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And we can convert these two numbers by wrapping that with the number method and again wrapping it with

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the rounded brackets and having the value passed inside.

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So that will force A and B to be numeric and in fact, allowing us to add them together and return back

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15.

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So try that one out as well.