function doSomething(x) { if(typeof(x) === 'string') { alert('x is a string') } else if(typeof(x) === 'number') { alert('x is a number') } }
> typeof "foo" "string" > typeof true "boolean" > typeof 42 "number" if(typeof bar === 'number') { //whatever }
//typeof() will return the type of value in it's parameters. //some examples of types: undefined, NaN, number, string, object, array //example of a practical usage if (typeof(value) !== "undefined") {//asuming value is already set //execute code }
typeof operando
> typeof "foo" "string" > typeof true "boolean" > typeof 42 "number"
console.log(typeof 'blubber');