js check string have number code example

Example 1: check if string only contains integer digits numbers javascript

let val = '1234567890' 
let isnum = /^\d+$/.test(val);
if (isnum) {
  // val is a number
}

Example 2: javascript is variable a string

if (typeof myVar === 'string'){
    //I am indeed a string
}

Example 3: js string have number js

var hasNumber = /\d/;   
      hasNumber.test("ABC33SDF");  //true
      hasNumber.test("ABCSDF");  //false

Example 4: javascript check if string is number

function isNumeric(num){
  return !isNaN(num)
}
isNumeric("23.33"); //true, checking if string is a number.