JavaScript配列内蔵関数

push

let array = ['강북구', '강남구', '강동구']

array.push('강서구')

console.log(array)
// [ '강북구', '강남구', '강동구', '강서구' ]

forEach

let newArray = ['윤승근', '고효민', '김지호', '나민지']

newArray.forEach((people) => {
    console.log(people)
})
// 윤승근
// 고효민
// 김지호
// 나민지

indexOf

let newArray = ['윤승근', '고효민', '김지호', '나민지']

let nameIndex = newArray.indexOf('고효민')

console.log(nameIndex) 
// 1

findIndex

let peopleInfo = [
    {
        id : 1,
        name : '윤승근',
        age : 28
    },
    {
        id : 2,
        name : '고효민',
        age : 28
    },
    {
        id : 3,
        name : '김지호',
        age : 28
    },
    {
        id : 4,
        name : '나민지',
        age : 28
    }
]

let newIndex = peopleInfo.findIndex(find => find.name === '김지호')

console.log(newIndex)
// 2

find

let peopleInfo = [
    {
        id : 1,
        name : '윤승근',
        age : 28
    },
    {
        id : 2,
        name : '고효민',
        age : 28
    },
    {
        id : 3,
        name : '김지호',
        age : 28
    },
    {
        id : 4,
        name : '나민지',
        age : 28
    }
]

let newIndex = peopleInfo.find(find => find.name === '김지호')

console.log(newIndex)
{ id: 3, name: '김지호', age: 28 }

let peopleInfo = [
    {
        id : 1,
        name : '윤승근',
        age : 28
    },
    {
        id : 2,
        name : '고효민',
        age : 28
    },
    {
        id : 3,
        name : '김지호',
        age : 28
    },
    {
        id : 4,
        name : '나민지',
        age : 28
    }
]

let newPeopleInfo = peopleInfo.filter(find => find.name === '나민지')

console.log(newPeopleInfo)
// [ { id: 4, name: '나민지', age: 28 } ]

splice

let array = ['윤승근', '고효민', '김지호', '나민지']

let index = array.indexOf('고효민')

let newArray = array.splice(index, 2)

console.log(array) 
// [ 윤승근, 나민지 ]

console.log(newArray)
// [ 고효민, 김지호 ]

slice

let array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

let newArray = array.slice(0, 5)

console.log(newArray)
// [ 1, 2, 3, 4, 5 ]

shift

let array = ['강북구', '강남구', '강동구', '강서구']

let arrayValue = array.shift();

console.log(arrayValue)
// 강북구

console.log(array)
// [ '강남구', '강동구', '강서구' ]

unshift

let array = ['c#', 'java', 'python', 'swift']

let arrayValue = array.unshift('javascript');

console.log(array)
// [ 'javascript', 'c#', 'java', 'python', 'swift' ]

pop

let array = ['강북구', '강남구', '강동구', '강서구']

let arrayValue = array.pop();

console.log(arrayValue)
// 강서구

console.log(array)
// [ '강북구', '강남구', '강동구' ]

concat

let arrayOne = ['강북구', '도봉구', '노원구']

let arrayTwo = ['강남구', '송파구', '강동구']

let newArray = arrayOne.concat(arrayTwo);

console.log(newArray)
// [ '강북구', '도봉구', '노원구', '강남구', '송파구', '강동구' ]

join

let array = ['windows', 'ios', 'ubuntu']

let newArray = array.join();

console.log(newArray)
// windows,ios,ubuntu

let newArray2 = array.join((' '))

console.log(newArray2)
// windows ios ubuntu (스페이스로 구분)