javascript check type code example

Example 1: javascript typeof shows object

What value it has 	 			What the output shows you 
 						when you write |console.log(typeof(variable);
Undefined:						"undefined"
Null:							"object"
Boolean:						"boolean"
Number:							"number"
String:							"string"
Function object:				"function"
E4X XML object:					"xml"
E4X XMLList object:				"xml"
NodeList						"Nodelist [more data]"
HTMLCollection					"HTMLCollection(1) [more data]"

Example 2: javascript detect if object is date

var myDate=new Date();
if(myDate instanceof Date){
    //im a hot Date
}

Example 3: javascript find type of variable

> typeof "foo"
"string"
> typeof true
"boolean"
> typeof 42
"number"

if(typeof bar === 'number') {
   //whatever
}

Example 4: check type javascript

console.log(typeof "how are you?")
"string"
console.log(typeof false) / console.log(typeof true)
"boolean"
console.log(typeof 100)
"number"

Example 5: node js check type of variable

if (typeof i != "number") {
    console.log('This is not number');
}

Example 6: 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
}