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JavaScript JavaScript Numbers Working with Numbers Convert Strings to Numbers

Posted by Paul May
Paul May
3,432 Points

When to parseInt()

Are there any disadvantages to converting the input directly to an integer if you know that it will only be used for number operations? For example in this video is there anything wrong with doing something like 

const HTMLBadges = parseInt(prompt("How many HTML badges do you have?"));

over something like 

let HTMLBadges = prompt("How many HTML badges do you have?");
HTMLBadges = parseInt(HTMLBadges);

2 Answers

Steven Parker
Steven Parker
229,644 Points
Steven Parker
Steven Parker
229,644 Points

There's no difference if you aren't going to be doing any error checking. But if you were, it might be nice to keep the original string so that you could try other operations on it and/or repeat it back to the user in an error message.

Hengly AUN
seal-mask
.a{fill-rule:evenodd;}techdegree
Hengly AUN
Full Stack JavaScript Techdegree Student 3,225 Points
Hengly AUN
.a{fill-rule:evenodd;}techdegree
Hengly AUN
Full Stack JavaScript Techdegree Student 3,225 Points

The disadvantage of this: const HTMLBadges = parseInt(prompt("How many HTML badges do you have?"));

If the user entered let's which is not number, the HTMLBadges will never get any value.

Because, it was defined as the " const ", so that value will never able to change.