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JavaScript JavaScript Basics (Retired) Creating Reusable Code with Functions Giving Information to Functions

H Yang
H Yang
2,066 Points

Strings & numbers

When I wrote out the practice program I used parseInt to parse the length and width into integers. I see here that JavaScript default assumes numbers in the function are numbers and not strings. Is there a consistent way to remember when things are entered as strings versus numbers?

1 Answer

Jason Welsh
.a{fill-rule:evenodd;}techdegree seal-36
Jason Welsh
Treehouse Project Reviewer

Generally, if a number is surrounded by quote marks ("3", '-67.43e5', etc.) it is treated as a string. And if you use something like the prompt() method to prompt the user to type a number, that is also an string and you need to parse the value to convert it to a number.

Other than that, everything that you supply as data in numerical form will be treated like a number - for example, it you have a function that accepts one or more parameters and you supply a number to it ex:

function calcArea(length, width) {
    var area = length*width;
    return area;
calcArea(55, 99);

In that example, the parameters would be treated as numbers.

H Yang
H Yang
2,066 Points

That was very clear. Thanks