February 2022
Beginner to intermediate
784 pages
24h 53m
Korean
Content preview from 자바스크립트 완벽 가이드
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JavaScript
164
6장 객체
propertyIsEnumerable()
은
hasOwnProperty()
를 더 제한한 버전입니다. 이 메서드
는 지정된 프로퍼티가 자체 프로퍼티이며
열거 가능
열거 가능 속성이
true
일 때만
true
를 반
환합니다. 일부 내장 프로퍼티는 열거 불가입니다. 일반적인 자바스크립트 코드로
생성한 프로퍼티는 모두 열거 가능이며 14.1절에서 열거 가능 프로퍼티를 열거 불
가로 만드는 방법을 설명합니다.
let o
=
{ x: 1 };
o.propertyIsEnumerable("x") //
=
> true: o
에는
열거
가능
프로퍼티
x
가
있습니다
.
o.propertyIsEnumerable("toString") //
=
> false:
자체
프로퍼티가
아닙니다
.
Object.prototype.propertyIsEnumerable("toString") //
=
> false:
열거
불가입니다
.
in
연산자 대신 그냥 프로퍼티를 검색하고
!= =
을 써서
undefined
가 아님을 확인하
는 경우도 많습니다.
let o
=
{ x: 1 };
o.x !
==
undefined //
=
> true: o
에는
프로퍼티
x
가
있습니다
.
o.y !
==
undefined //
=
> false: o
에는
프로퍼티
y
가
없습니다
.
o.toString !
==
undefined ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.