JS의 배열 메서드 - toString()

코드 예

const number = 12345;
const string = "Javascript";
const boolean = true
const array = [1,2,3];
const mixedArray = [1,2,3,"HTML","CSS"]
let nestedArray = [1, 2, 3, ["Html", "JS"]];


const numberToString = number.toString()
const stringToString = string.toString()
const booleanToString = boolean.toString()
const arrayToString = array.toString()
const mixedToString = mixedArray.toString()
const nestedToString = nestedArray.toString()


console.log(typeof numberToString)
console.log(typeof stringToString)
console.log(typeof booleanToString)
console.log(typeof arrayToString)
console.log(typeof mixedToString)
console.log(typeof nestedToString)

console.log(numberToString)
console.log(stringToString)
console.log(booleanToString)
console.log(arrayToString)
console.log(mixedToString)
console.log(nestedToString)

출력 -

string
string
string
string
string
string
12345
Javascript
true
1,2,3
1,2,3,HTML,CSS
1,2,3,Html,JS

예외 -

const Null = null
const Undefined = undefined
const object = {name:"shubham",age:21}


const undefinedToString = Undefined.toString()
const nullToString = Null.toString()
const objectToString = object.toString()

console.log(objectToString)

출력 -

TypeError: Cannot read properties of undefined (reading 'toString')
TypeError: Cannot read properties of null(reading 'toString')
[object Object]

JSON.stringify() -

const object = {name:"shubham",age:21}
const objectToString = JSON.stringify(object)
console.log(objectToString)

출력 -

{"name":"shubham","age":21}

비교하여 사용 -

const number = 12345;
const string = "12345";

const compare = number === string;
//false due to different datatype
const compare = number.toString() === string;
//true due to same datatype