typeof 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: isPrototypeOf js
/"Checks if an object exists in another object's prototype chain."/
function Bird(name) {
this.name = name;
}
let duck = new Bird("Donald");
Bird.prototype.isPrototypeOf(duck);
// returns true
Example 3: type of variable js
// get type of variable
var number = 1
var string = 'hello world'
var dict = {a: 1, b: 2, c: 3}
console.log(typeof number) // number
console.log(typeof string) // string
console.log(typeof dict) // object
Example 4: javascript find type of variable
> typeof "foo"
"string"
> typeof true
"boolean"
> typeof 42
"number"
if(typeof bar === 'number') {
//whatever
}
Example 5: 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 6: node js check type of variable
if (typeof i != "number") {
console.log('This is not number');
}