javascript how to check type code example

Example 1: check type string javascript

if (typeof myVar === 'string' || myVar instanceof String)
// it's a string
else
// it's something else

Example 2: 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 3: 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 4: javascript check if variable is object

//checks if is object, null val returns false
function isObject(val) {
    if (val === null) { return false;}
    return ( (typeof val === 'function') || (typeof val === 'object') );
}
var person = {"name":"Boby Snark"};
isObject(person);//true

Example 5: check data type in js

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