[JavaScript] 40. Basic Array Operations(Methods)

Array Operation(methods) : unshift, pop, indexOf, includes가 있습니다.

 

// 40. Basic Array Operations(Methods)
const friends = ['Kim', 'Lee', 'Park'];

// Add Elements
const newLength = friends.push('Gang');
console.log(friends); // =>['Kim', 'Lee', 'Park']
console.log(newLength); // -> 4

friends.unshift('John');
console.log(friends);

// Remove elements
friends.pop(); // Last elements 제거
const popped = friends.pop();
console.log(popped); // popped -> 지워진 elem 나옴
console.log(friends);

friends.shift(); // First elem 제거
console.log(friends);

console.log(friends.indexOf('Lee'));
console.log(friends.indexOf('Kim'));

friends.push(23);
console.log(friends.includes('Gang'));
console.log(friends.includes('Park'));
console.log(friends.includes(23)); // true
console.log(friends.includes('23')); // false -> include: strict equality


if (friends.includes('Kim')){
    console.log('You have a friend called Kim');
}