typeof null 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: check data type in js

typeof("iAmAString");//This should return 'string'
//NO camelCase, as it is a JS Keyword

Example 4: 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 5: javascript check type of variable var

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

Example 6: js null is object typeof

In the first implementation of JavaScript, JavaScript values were represented 
as a type tag and a value. The type tag for objects was 0. null was represented 
as the NULL pointer (0x00 in most platforms). Consequently, null had 0 as type 
tag, hence the "object" typeof return value. (reference)

A fix was proposed for ECMAScript (via an opt-in), but was rejected. 
It would have resulted in typeof null === 'null'.