parseInt and Radix

Everyone knows that the parseInt function within JavaScript turns your decimal number or string into a rounded integer. parseInt turns 10.937 into 10, 0.2 into 0, and “someValue” into NaN.  If you use parseInt without a radix, however, you’ll receive a warning that no radix has been provided.  In most cases, the radix you want to use is 10:

parseInt(10.83, 10); // 10, no warning
parseInt(.83, 10); // 0, no warning

parseInt(0.8); // 8, unintended result
parseInt(0.8, 10); // 0, intended result

Using a 10 radix means the number is parsed with a base 10 and thus turns the number into the integer you’re expecting, without the annoying warning.  The radix is important if you’re need to guarantee accuracy with variable input (basic number, binary, etc.).

For best results, always use a radix of 10!

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