JaeYeopHan

function flatten(arr) {
  return function f(arr, newArr) {
    arr.forEach(function(v)) {
      Array.isArray(v) ? f(v, newArr) : newArr.push(v);
    });
    return newArr;
  }(arr, []);
}

JaeYeopHan

export function requiredParam (param) {
  const requiredParamError = new Error(
   `Required parameter, "${param}" is missing.`
  )
  // preserve original stack trace
  if (typeof Error.captureStackTrace === ‘function’) {
    Error.captureStackTrace(
      requiredParamError, 
      requiredParam
    )

JaeYeopHan

export function pipe(...fns) { 
  return param => fns.reduce(
    (result, fn) => fn(result), 
    param
  )
}

JaeYeopHan

export const getFilteredPair = (base: object, checker: (value: any) => boolean): object => {
	return Object.keys(base).reduce((acc, key) => {
		if (checker(key)) {
			acc[key] = base[key];
		}
		return acc;
	}, {});
}

JaeYeopHan

const minify = require('html-minifier').minify;
const fs = require('fs');

class HtmlMinifierPlugin {
  constructor(options) {
      this.options = options;
  }
  apply(compiler) {
    compiler.plugin("emit", (compilation, callback) => {
        fs.readFile(this.options.template, 'utf-8', (err, html) => {

JaeYeopHan

export const delay = (time: number) => {
	return new Promise((resolve, reject) => {
		setTimeout(resolve, time);
	});
};

JaeYeopHan

class Store {
  constructor(state = {}, actions = {}) {
    this.state = state;
    this.actions = actions;
    this.dispatch = (action, data) => {
      const newMergedData = this.actions[action](this.state, data);
      Object.assign(this.state, newMergedData);
    };
  } 
}

JaeYeopHan

export class Marker extends EventEmitter {
  constructor(
    private id: number,
  ) {
    super();

    document.querySelector("marker").addEventListener("click", () => {
      // do something
      this.trigger("card_action", this.id);
    });

JaeYeopHan

class Card extends React.Component<CardProps> {
  do() {
    // do something...
  }
  render() {
    const { index } = this.props;
  
    return ( ... );
  }
}

JaeYeopHan

const counter = (state = 0, action) => {
  switch (action.type) {
    case 'INCREMENT':
      return state + 1;
    case 'DECREMENT':
      return state - 1;
    default: 
      return state;
  }
}