parseInt(): start of a number, not validate the entire input

Useful to know

Number.parseInt() reads an integer from the beginning of the allowed number part. For example, Number.parseInt("42px", 10) gives 42. This does not prove that the entire string is a valid numeric record . [1]

Set the base when you expect a decimal system, and separate the parsing from the checking of the form. In a "42px" quantity form, it is likely to be rejected despite the result obtained. The method is not rounding any number; in a textual input, it follows read rules, not the general rules of mathematical rounding.