There are two main ways to convert a string to a number in JavaScript. One way is to parse it and the other way is to change its type to a Number. All of the tricks in the other answers (e.g., …

None of the answers I see at the moment correctly convert -0 to "-0". Note that -0..toString() might appear to work, but it's working by converting 0 to "0", then applying the minus sign to it, …

If someone wants to know if a string contains a number, it seems to me that they would want to know if it contains a number, and 1e+30 is a number. Certainly if I were testing a string for a …

Below is a very irritating example of how JavaScript can get you into trouble: If you just try to use parseInt() to convert to number and then add another number to the result it will concatenate …

2 What would be the most efficient and safe method to convert a Decimal Integer String to a number in a time-critical loop or function where there are thousands (sometimes 100's …

Aug 20, 2009 · Does anyone know how can I check whether a variable is a number or a string in JavaScript?

20 This question already has answers here: How can I convert a string to an integer in JavaScript? (32 answers)

I have a number in Javascript, that I know is less than 10000 and also non-negative. I want to display it as a four-digit number, with leading zeroes. Is there anything more elegant than the …

Mar 23, 2016 · Yes it gets a boolean from the < result and coerces it to string, but by then it's too late to affect how the comparison worked. JS < operator behavior depends on its two …

Here's another interesting, readable way to check if a string contains only digits. This method works by splitting the string into an array using the spread operator, and then uses the every() …