#8 Type Conversion & Coercion in JavaScript

[Music] welcome back aliens my name is davin rady and let's continue with this series on javascript now in this video we'll talk about type conversion and type coercion now why do we have two different words let's understand that now first of all it doesn't matter which language you work with you have something in common right you actually work with data but sometimes you want to convert your data in specific format example we have talked about data types right we have numbers string boolean and there might be an option or there might be a requirement where you have to convert your data from number to string or from string to number or from number to boolean how do we do that now let's say let me create a variable here so i will say num this time i'm using a dark theme basically a high contrast so let me know your feedback in the comments section uh so finally we are on the dark theme yeah let me create a number here right so this is a number now we have seen how do you print the type of data of course when you want to print the data as it is we can simply print num right now this will print data example if i run this code you got 6 but what if you want to print a type of it in that case you can use a very special operator which we have seen earlier which is type off and you can print the type of num so basically we are printing two things here we are printing num and we are printing type of num and let's see what happens and you can see we got six and we got number that means the type of this num is number that is working right but what if i want to store this num in a different format i want this to be in string format can we do this now you will think hey why do we do that so example let's say if you want to store a pin called a zip code of area which is the best format should you store the zip code in number or in a string format see whenever you don't want to perform any operation it's better to store that in a string format example telephone number zip code or whatever big number you have when you want to perform calculation that's why number makes sense right so here i want to store this six in a string format in that case you have to convert that right you have to perform some operation so we have a specific thing called a string so we'll pass string here when you pass this number 6 inside a string it will give you a string format so this number is getting stored in a string format now will it work let's try so let me just run this code once again and you can see we got six no change in data of course you have not got s i x what you got is number six and you got a string okay so this is working right and you can also do reverse if you have a number in a string format let's say one two three so now if you run this code of course the data is in string format 123 is in string format and if you want to perform operation you have to convert that into number in order to do that we can simply say number and you can give a bracket and this will work right so if you run this code you got number the same thing again you can do with boolean okay so you can convert a number up with boolean but that's a different thing we'll do that later the interesting thing is this is type conversion right you are able to convert a number in different format this is explicit conversion because basically you as a developer you are trying to convert a data from one format to the format it's working right but then javascript went ahead javascript says hey you have type conversions that's great let me give you something called type conversion now what it means so let's say i have a number here i'll say num or maybe i will not go for any specific name because num represents a name right so i will go with let's say x i know it's not a good variable name but just for the example here we can go with it so let's say i have a variable x and i want to print x here and i want to print the type of it of course we are printing the data we are printing the type of this data and the output you are getting is undefined undefined of course that makes sense right now what i will do here is i will assign data to it so when you assign the data it will change the type of it now what did i want to assign let me just do that here so i will say x is equal to six or maybe a different number this time so let's go for x equal to eight now if we do the same thing i just want to copy and paste actually where i'm just reusing the code right so after changing the value of x now let's try so you can see we got undefined undefined because that was the first time and then we got eight number because this is the number if i change the same thing again let's say i want to perform some operation so i can simply say x is equal to i want to add x with a string what do you think what would happen and what type of string i want to add maybe i just want to add empty string i don't even have some specific type of string here right it's it's an empty string now what will happen of course i should also print the console here okay now let me try and you can see this time we got string so basically whenever you have a number and you are you have a string this plus operator here it got confused the idea behind a plus operator is to add two numbers right but this time we have a number and a string confusion right so coercion comes into picture so javascript says okay in this case every time you have two different data and you want to perform some operation you have to come to some consensus right either both has to be same type it either it should be both string or both number so in this case it goes for the string because we have string at one end now whenever you have string and when you use plus operator it is actually concatenation so basically we are joining two strings for example let's say you have naveen you have ready two different strings you use a plus orbital basically you are concatenating it in this case as well even if you have x which is the number and you have a string it will convert that into string but not always not always when you use a string a number it will give the same results example let's say at this point if you see this is a type of string right this x is a type of string what if i do x equal to x minus 2. now you tell me what will happen of course i have to print it as well so pause this video and let me know what will happen because x is a string now 2 is a number so how it should behave should we get 8 minus 2 6 or should we get some weird answer or maybe it should be nand right which is because you are subtracting a number from a string and that is weird so let's let's see what happens so if you run this code i hope you have answered that in the comment section you got number so this is what happens when you have a subtraction operator with a string it will convert that into number so this is type coercion so based on what type of operator you're using based on what's the requirement javascript engine will change that for you in fact we can also do with boolean so we know right boolean is true or false now the way you can manipulate boolean is with the help of some operators one of them is exclamation exclamation will simply replace or it will do the opposite so if it is true it will give you false if it is false it will give you true right so exclamation actually means not so there's a not operator with boolean which will change the type so from true to false false true now let me just do that so i will say x equal to not x so even if it is a number format so you can see x in this case is number right so you are applying a not operator or number because the naught will only work with boolean right and you are giving a number so in this case it will convert that into boolean and then it will perform the not operation and let's see what happens but the question is will you get true or false so even if i say it converts this from number to boolean what happens is it true or false let's try let's run this code oh i'm not printing it my bad let me print this and you can see we got false boolean so boolean makes sense but why false that means you are performing an operation the output of that operation is false that means initially the value of x was true that means if you try to convert a number into boolean if that number is 6 it will give you true only 6 it's actually any number example let me just do that so what i will do is i will just go to console and console.log and let me convert a number let's say i have a number seven and i want to convert this into boolean how do we convert a number into boolean the same way we did it for the number and string with the help of that keyword number string here let me use boolean so i'm passing 7 to a boolean right so it will convert this 7 into a boolean format but what you will get you will you get true or false let's try so when i run this code you can see we got true okay so for six it just giving you true for seven is giving you true i thought it will be even odd so even numbers will get true or number will get false but that's not the case every number is giving you true let me try negative number so if i say minus seven let's see it's still true okay now after trying out all the different combinations let's try zero and the moment you try zero and if you underscore you can see we got false that means all the numbers are true only zero is false why is because the actual implementation of boolean happens in that way 0 is false 1 is true right if it is not 0 everything is true but you can actually calculate with each number so they simply go with simple formula if it is 0 it's false if it is all the other numbers it is true and this is called uh truthy and the falsie values i know that that's tricky it's not just with numbers it's also with other types example let me convert into boolean of type null now what will happen if we try to convert null into boolean and if you're on this code you can see we got false so even null is a false value so whenever you try to convert something into boolean and if that gives you false it is false value if you pass something and if you're trying to convert that into boolean if it is giving you true that's called a truthy value example after some time will start working with functions objects whatever your data you pass so if you try to convert object into boolean it will give you true if you try to pass a function to and convert into boolean it will give you true cool what about undefined let me just try that so we'll try it with undefined also it will give you false so these are all false values okay apart from this everything is truthy value so you can see the list if you have something like this and if you try to convert these things into boolean you will get false and all the other thing will give you true uh let me just try with stringer we have not tried with string yet so what i will do is i'll pass the string like naveen now what happens nobody is true or false of course nothing is true let's try and you can see we got true now since it's not a part of the false values it's true so just reiterate whenever you have a number and a string it will convert that into string when you apply the addition operator but when you perform this subtraction operator it will convergent number so javascript is smart enough to know what should be done and that's one thing i love and hate about javascript we love this thing because it helps you it actually understands what you need and it will give the output the reason i also hate it is because it tries to convert things the way it wants sometimes you don't intend to do that and you want others but javascript says okay you're doing this i will allow you and i will help you here we don't want your help we want others because this will eventually lead to bugs okay and that's why you have to very alert when you're doing these operations in fact we have some more ways example let's say i want to do plus operator here right so we have x in string format here and you want to okay let me just remove this part just to make it simple yeah so we have x which is string format right so if you run this code so you can see we got 82 because you have eight here which is x and then you got two so you got 82. but in this case i want to convert this into a number in that case you can use unary operators of course we'll talk about orbitals later in detail but so whenever you add a plus here it tries to convert this string into number let's try that and you can see we got numbers so we got 10 which is the addition of eight and two and you've got a number okay there are more ways actually to convert the string into integer or the other format so let me just try that so let's say we have x and the value of x is one two three navin okay now in this case i want to convert this into a number format but of course you can't convert that into number format right because we have naveen there so if you try to do that with the help of a number function so let's say if i do let me just print that first as it is let's see what happens if you print this and you can see we got one two three naveen okay that works but if you try to convert that into number because we did that before let's see what happens so if we try to do that and if you run this code you can see we got nan which is not number we don't want this what we want is it should be able to convert that and at least fetch these first integer values so in this case you can actually use parseint so pass int is a special function which will accept a string it will try to convert that number okay it will do its hard work to convert a string into number and you can see we got 123 but what happens if you have a character at the start in this case it will not work so i have to make sure that you have numbers at the start so it will try to convert that into numbers right so that's how you can do it uh so try out different functions you can go to google and search for different type conversions functions and you will get those so i hope you enjoyed this video let me in the comments section and do some stuff for the videos bye you

Channel: Telusko

Views: 18,519

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Id: wFiVtqe1osM

Length: 12min 53sec (773 seconds)

Published: Wed May 19 2021