Detail the four types of identification methods in JavaScript

The details are as follows:

1.typeof

Output a lowercase string that begins with a letter

【 functions 】

[a] Can identify standard types (identify Null as object)
[b] cannot identify specific object types (except Function)

[example]

console.log(typeof "jerry");//"string"
console.log(typeof 12);//"number"
console.log(typeof true);//"boolean"
console.log(typeof undefined);//"undefined"
console.log(typeof null);//"object"
console.log(typeof {name: "jerry"});//"object"
console.log(typeof function(){});//"function"
console.log(typeof []);//"object"
console.log(typeof new Date);//"object"
console.log(typeof /\d/);//"object"
function Person(){};
console.log(typeof new Person);//"object"

2.Object.prototype.toString

[Output] [object data type] as a string

【 functions 】

[a] recognizes both standard and built-in object types
[b] does not recognize custom types

[Construction method]

function type(obj){
　　return Object.prototype.toString.call(obj).slice(8,-1).toLowerCase();
}  

[Example 1]

console.log(Object.prototype.toString.call("jerry"));//[object String]
console.log(Object.prototype.toString.call(12));//[object Number]
console.log(Object.prototype.toString.call(true));//[object Boolean]
console.log(Object.prototype.toString.call(undefined));//[object Undefined]
console.log(Object.prototype.toString.call(null));//[object Null]
console.log(Object.prototype.toString.call({name: "jerry"}));//[object Object]
console.log(Object.prototype.toString.call(function(){}));//[object Function]
console.log(Object.prototype.toString.call([]));//[object Array]
console.log(Object.prototype.toString.call(new Date));//[object Date]
console.log(Object.prototype.toString.call(/\d/));//[object RegExp]
function Person(){};
console.log(Object.prototype.toString.call(new Person));//[object Object]

[Example 2]

function type(obj){
  return Object.prototype.toString.call(obj).slice(8,-1).toLowerCase();
}
console.log(type("jerry"));//"string"
console.log(type(12));//"number"
console.log(type(true));//"boolean"
console.log(type(undefined));//"undefined"
console.log(type(null));//"null"
console.log(type({name: "jerry"}));//"object"
console.log(type(function(){}));//"function"
console.log(type([]));//"array"
console.log(type(new Date));//"date"
console.log(type(/\d/));//"regexp"
function Person(){};
console.log(type(new Person));//"object"

3.constructor

[Output] function data type (){[native code]} or function custom type (){}

【 functions 】

[a] recognizes standard types, built-in object types, and custom types
[b] cannot identify undefined and null and will report an error

[Construction method]

function type(obj){
  var temp = obj.constructor.toString();
  return temp.replace(/^function (\w+)\(\).+$/,'$1');
}

[Example 1]

console.log(("jerry").constructor);//function String(){[native code]}
console.log((12).constructor);//function Number(){[native code]}
console.log((true).constructor);//function Boolean(){[native code]}
//console.log((undefined).constructor);// An error 
//console.log((null).constructor);// An error 
console.log(({name: "jerry"}).constructor);//function Object(){[native code]}
console.log((function(){}).constructor);//function Function(){[native code]}
console.log(([]).constructor);//function Array(){[native code]}
console.log((new Date).constructor);//function Date(){[native code]}
console.log((/\d/).constructor);//function RegExp(){[native code]}
function Person(){};
console.log((new Person).constructor);//function Person(){}

[Example 2]

function type(obj){
  var temp = obj.constructor.toString().toLowerCase();
  return temp.replace(/^function (\w+)\(\).+$/,'$1');
}
console.log(type("jerry"));//"string"
console.log(type(12));//"number"
console.log(type(true));//"boolean"
//console.log(type(undefined));// error 
//console.log(type(null));// error 
console.log(type({name: "jerry"}));//"object"
console.log(type(function(){}));//"function"
console.log(type([]));//"array"
console.log(type(new Date));//"date"
console.log(type(/\d/));//"regexp"
function Person(){};
console.log(type(new Person));//"person"

4.instanceof

[Output] true or false

【 functions 】

[a] recognizes built-in object types, custom types, and their parent types
[b] does not recognize the standard type and returns false
[c] cannot identify undefined and null and will report an error

[example]

console.log("jerry" instanceof String);//false
console.log(12 instanceof Number);//false
console.log(true instanceof Boolean);//false
//console.log(undefined instanceof Undefined);// An error 
//console.log(null instanceof Null);// An error 
console.log({name: "jerry"} instanceof Object);//true
console.log(function(){} instanceof Function);//true
console.log([] instanceof Array);//true
console.log(new Date instanceof Date);//true
console.log(/\d/ instanceof RegExp);//true
function Person(){};
console.log(new Person instanceof Person);//true
console.log(new Person instanceof Object);//true

The above content is a detailed explanation of the four types of identification methods in JavaScript, I hope you enjoy.