How to convert a string to an integer in JavaScript?

Converting a string to an integer in JavaScript is pretty straightforward, and you’ve got several options depending on what exactly you're trying to do. Here's how you can go about it:

1. Using parseInt()

This is the most commonly used method.

  let num = parseInt("42"); // returns 42

• It parses a string and returns an integer.
  
• It stops parsing at the first non-digit character.
  
• You can also specify the radix (base), which is super helpful.

  let binary = parseInt("1010", 2); // returns 10

2. Using Number()

This is a bit stricter than parseInt():

let num = Number("42"); // returns 42
let invalid = Number("42abc"); // returns NaN

• It tries to convert the whole string.
  
• Returns NaN if the string isn’t fully numeric.
  

3. Using Unary + Operator

A quick and clean way to convert:

  let num = +"42"; // returns 42

• It’s very concise.
  
• But not very readable for beginners.
  

Things to Watch Out For:

• Leading/trailing spaces are usually fine, but mixed characters can break conversions.
  
• Always validate the result using isNaN() to avoid unexpected behavior.
  

 Pro tip: Always sanitize user inputs before conversion to avoid bugs or unexpected values.