Array APIs - push(), pop(), unshift(), shift()

push :  배열 맨 뒤에 요소 추가

push(...items: T[]): number;
/**
 * Appends new elements to the end of an array, and returns the new length of the array.
 * @param items New elements to add to the array.
 */

const animal = ['🐶', '🐱'];
animal.push('🐹');
console.log(animal); //['🐶', '🐱', '🐹']

animal.push('🐰', '🐼');
console.log(animal); //['🐶', '🐱', '🐹', '🐰', '🐼']

 

pop :  배열 마지막 요소 제거

pop(): T | undefined;
/**
 * Removes the last element from an array and returns it.
 * If the array is empty, undefined is returned and the array is not modified.
 */

const animal = ['🐶', '🐱'];
const result = animal.pop();

//제거된 요소 반환
console.log(result); //🐱
console.log(animal); //['🐶']

 

unshift : 배열 맨 앞에 요소 추가

unshift(...items: T[]): number;
/**
 * Inserts new elements at the start of an array, and returns the new length of the array.
 * @param items Elements to insert at the start of the array.
 */

const animal = ['🐶', '🐱'];
animal.unshift('🐰');
console.log(animal); //['🐰', 🐶', '🐱']

animal.unshift('🐵', '🦊');
console.log(animal); //['🐵', '🦊', '🐰', 🐶', '🐱']

 

shift : 배열 첫 번째 요소 제거

shift(): T | undefined;
/**
 * Removes the first element from an array and returns it.
 * If the array is empty, undefined is returned and the array is not modified.
 */

const animal = ['🐶', '🐱'];
const result = animal.shift();

//제거된 요소 반환
console.log(result); //🐶
console.log(animal); //['🐱']