Answers for "js how to conirm a string is a number"

javascript check if string is number

// native returns true if the variable does NOT contain a valid number
isNaN(num)

// can be wrapped for making simple and readable
function isNumeric(num){
  return !isNaN(num)
}

isNumeric(123)         // true
isNumeric('123')       // true
isNumeric('1e10000')   // true (This translates to Infinity, which is a number)
isNumeric('foo')       // false
isNumeric('10px')      // false

converst strig in number in js

const numberInString = "20"; 
console.log(typeof(numberInString)) // typeof is string this is string in double quote " "
const numInNum = parseInt(numberInString) // now numberInStrings variable converted in an Integer due to parseInt
console.log(typeof(numInNum)) // this tell us the type of numInNum which is now a number