![3.비동기처리
EventLoop가SingleThread이며,workerthread를활용하여작업을처리한다
참고:[NodeJS]nodejs는single-thread가아니다51Scrum 7](https://image.slidesharecdn.com/nodejs-191124041849/85/JAVA-NodeJS-7-320.jpg)
![모듈설치
$> npm install axios
결과
$> find . -type d -maxdepth 1 | sed -e "s/[^-][^/]*// |/g" -e "s/|([^ ])/|-1/"
|-node_modules
| |-ms
| |-follow-redirects
| |-is-buffer
| |-axios
| |-debug
axios와의존성관계가있는follow-redirects,is-buffer모듈설치됨
51Scrum 21](https://image.slidesharecdn.com/nodejs-191124041849/85/JAVA-NodeJS-21-320.jpg)
![참고자료#1
NODE.JSVSJAVA:CHOOSINGABACK-ENDLANGUAGEFORLARGEAPP
DEVELOPMENT
빠르게서비스를개발할수있는Node.js
Helloworld/Webserver
nodejs.dev
UnderstandingEventLoopinNodeJS
[NodeJS]nodejs는single-thread가아니다
51Scrum 28](https://image.slidesharecdn.com/nodejs-191124041849/85/JAVA-NodeJS-28-320.jpg)
JAVA 개발자가 시작하는 NodeJS
- 2. 저는! 2005년부터Java언어를기반으로2018년까지주로WEB을개발 - 렌트카 관리, 제약회사, 쇼핑몰, 기상청 데이터 센터, 보안 솔루션 등 구축 2018년11월GSSHOP에입사하여NodeJS를사용시작 - 상품360, SRR, 심의포털, 트랜드몬, LMS몬, Q-FIT 등 구축 51Scrum 2
- 6. 2.javascript기반의FullStack개발 Front-end와Back-end를동일한언어인javascript를사용하여언어의변경에따른비용(시 간)최소화할수있다. 51Scrum 6
- 9. 알아야하는비동기동작 console.log("first"); setTimeout(() => {console.log('second')}, 0); //비동기 처리 console.log('third'); --- 결과 first third second 51Scrum 9
- 11. CallBack http.get('http://www.gsshop.com', function (res) { if (res.statusCode === 200) { console.log("first"); http.get('http://www.gsshop.com', function (res) { if (res.statusCode === 200) { console.log("second"); http.get('http://www.gsshop.com', function (res) { if (res.statusCode === 200) { console.log("third"); } }) } }) } }); 51Scrum 11
- 12. Promise const promiseExample = (msg) => { return new Promise((resolve, reject) => { http.get('http://www.gsshop.com', function (res) { if (res.statusCode === 200) { resolve(msg); }else{ reject('fail'); } }) }) } promiseExample('first').then(data => { console.log(data); return promiseExample('second'); }).then(data => { console.log(data); return promiseExample('third'); }).then(data => { console.log(data); }); 51Scrum 12
- 13. async&await const main = async () => { const first = await promiseExample('first'); console.log(first); const second = await promiseExample('second'); console.log(second); const third = await promiseExample('third'); console.log(third); } main(); 51Scrum 13
- 15. 잘못된사례 # 직렬 처리 const sample = async (list) => { for (const item of list) { await process(item); } console.log('Done!'); } 51Scrum 15
- 16. 처리방안 # 병렬 처리 const sample = async (list) => { const promises = list.map(process); //promise 형식을 리턴 받음 await Promise.all(promises); console.log('Done!'); } 51Scrum 16
- 21. 모듈설치 $> npm install axios 결과 $> find . -type d -maxdepth 1 | sed -e "s/[^-][^/]*// |/g" -e "s/|([^ ])/|-1/" |-node_modules | |-ms | |-follow-redirects | |-is-buffer | |-axios | |-debug axios와의존성관계가있는follow-redirects,is-buffer모듈설치됨 51Scrum 21