[javascript] module(export & import)

기본구조

app.js

import log, {getTime, getCurrentHour} from './myLogger.js'

log('my first test data');
log(`getTime is ${getTime()}`);
log(`current hour is ${getCurrentHour()}`)

myLogger.js

export default function log(data) {
  console.log(data);
}

export const getTime = () => {
  return Date.now();
}

export const getCurrentHour = () => {
  return (new Date).getHours();
}

class

app.js

import log, {MyLogger} from './myLogger.js'

const logger = new MyLogger();
log(logger.getLectures);

myLogger.js

export default function log(data) {
  console.log(data);
}

export class MyLogger {
  constructor(props){
    this.lectures = ['java', 'iOS']
  }
  
  getLectures() {
    return this.lectures;
  }
  
  getTime() {
    return Date.now();
  }
}