Question

 What's the value of num?

const num = parseInt('7*6', 10);

• A: 42
• B: "42"
• C: 7
• D: NaN

Answer 1

Answer: C

Only the first numbers in the string is returned. Based on the radix (the second argument in order to specify what type of number we want to parse it to: base 10, hexadecimal, octal, binary, etc.), the parseInt checks whether the characters in the string are valid. Once it encounters a character that isn't a valid number in the radix, it stops parsing and ignores the following characters.

* is not a valid number. It only parses "7" into the decimal 7. num now holds the value of 7.