how to use typeof in javascript code example

Example 1: javascript find type of variable

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

if(typeof bar === 'number') {
   //whatever
}

Example 2: check data type in javascript

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

Example 3: javascript typeof

exports.is = (data) => {
const isArray = Array.isArray(data) && 'array'
const isObject = data == {} && 'object'
const isNull =  data == null && 'null'

const isGrouping =  isArray || isObject || isNull
const isCheck = !isGrouping ? typeof data : isGrouping

const isTypeData = ['number','string','array','symbol','object','undefined','null','function', 'boolean']
const isMatch = isTypeData.indexOf(isCheck)
const isResult = isTypeData[isMatch]
return isResult
}

Example 4: how to use typeof in javascript

var someValue = 'this is string';
console.log(typeof(someValue)); // this will return string

Example 5: how to use typeof in javascript

console.log(typeof 93);
// Output = "number"

console.log(typeof 'Maximum');
// Output = 'string'

console.log(typeof false);
// Output = "boolean"

console.log(typeof anUndeclaredVariable);
// Output = "undefined"

Example 6: how to use typeof in 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
}