check type of object javascript 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: 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: javascript check if is object

obj = {
	"data": 123
}
arr = [
	"data", 
	123
]

function obj_or_arr(val) {
	if (typeof val === "object") { // return if is not array or object
		try {
			for(x of val)  // is no errors happens here is an array
				break;
			return "array";
		} catch {
			return "object"; // if there was an error is an object
		}
	} else return false; 
}

console.log(obj_or_arr(obj)) // object
console.log(obj_or_arr(arr)) // array
console.log(obj_or_arr(123)) // false
console.log(obj_or_arr("hello world")) // false
console.log(obj_or_arr(true)) // false
console.log(obj_or_arr(false)) // false

Example 4: check data type in js

typeof("iAmAString");//This should return 'string'
//NO camelCase, as it is a JS Keyword

Example 5: get type of object javascript

var obj = new String();
var str = "this is string";
            
typeof obj; // returns object
typeof str; // returns string