js check type of variable code example

Example 1: javascript how to know type of variable

var foo = "Hello";
console.log(typeof foo); // string

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: check data type in javascript

typeof("string"); //string
typeof(123); //number

Example 5: how to get type of variable in javascript

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

Example 6: javascript check type of variable var

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