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JavaScript JavaScript Numbers Working with Numbers Treating Strings As Numbers

Posted by Aissa Toumi
Aissa Toumi
1,419 Points

Why this did not happen when we worked with multiplying seconds with minutes

Why this did not happen when we worked with multiplying seconds with minutes

1 Answer

Laisvūnas Miškinis
Laisvūnas Miškinis
6,614 Points

While multiplying numbers there were created variables which by type were numbers

const secondsPerMin = 60;
// Notice no quotation marks. That means type of variable is number.

However when you use prompt() even if you type in number to the input field the prompt() function returns value as a string type (means that value you get from it is inside single quotation marks). When adding strings they just get stuck together because program doesnt see that as numbers (so in case of '10' + '5' you get '105')

const HTMLBadges = prompt('How many HTML badges you have?');
/* Returns value in a string type. 
Even if you type in number lets say 10 
prompt will return value of '10' (notice quotation marks). 
So in this case 2 prompt values gonna stick to each other like its a string. 
Thats why '10' + '5' you get '105'
*/
Elfar Oliver
Elfar Oliver
3,924 Points
Elfar Oliver
Elfar Oliver
3,924 Points

So if we were to use the typeof method he used at the end of the video in the age calculation, we'd see the difference?