how to check datatype in javascript code example

Example 1: get type of var js

function doSomething(x) {
  if(typeof(x) === 'string') {
    alert('x is a string')
  } else if(typeof(x) === 'number') {
    alert('x is a number')
  }
}

Example 2: type of javascript

//typeof() will return the type of value in its parameters.
//some examples of types: undefined, NaN, number, string, object, array

//example of a practical usage
if (typeof(value) !== "undefined") {//also, make sure that the type name is a string
  	//execute code
}

Example 3: check data type in javascript

typeof("string"); //string
typeof(123); //number

Example 4: javascript datatypes

dataTypes = {
    Numbers = 1,2,3, 100, 3.14
    Strings = 'Hello, World' "helloworld@gmail.com
    Boolean = true / false
    Null = 'Explicitly set a variable with no Value'
    Undefined = 'For variable that have not yet been defined'
    Object = 'Complex data structures - Arrays, Dates, Literals etc'
    Symbol = 'Used with objects' // usually not needed
}

Example 5: get type of var js

var x = 12345; 
console.log(typeof x) // number
x = 'string'; 
console.log(typeof x) // string
x = { key: 'value' };
console.log(typeof x) // object

Example 6: check data type in js

var x = "Hello World";
typeof x; // "string"