dewey92

module Main where

import Prelude

import Effect (Effect)
import Effect.Class (liftEffect)
import Effect.Aff (Aff, launchAff_)
import Node.FS.Aff as FS
import Node.Buffer as Buffer
import Node.Encoding (Encoding(..))

dewey92

// brand.ts
// use symbol, but don't export it!
declare const _brand: unique symbol;
export type Brand<Name, Type> = Type & { [_brand]?: Name }

// degree-module.ts
export type Celcius = Brand<'Celcius', number>;
export type Fahrenheit = Brand<'Fahrenheit', number>;

dewey92

// Counter.jsx
import * as React from 'react'
import { useCounterReducer } from './useCounterReducer'

const Counter = () => {
  const [[counter, effect], actions] = useCounterReducer();

  // Hooks ini hanya berfokus pada "side-effect" dari reducer di atas
  React.useEffect(() => {
    if (effect === 'INVALID_STATE') {

dewey92

// useCounterReducer.js
import * as React from 'react';

// Array destructuring disini sangat membantu code readability
const counterReducer = ([state, effect], action) => {
  if (action.type === 'INCREMENT') {
    return [state + 1];
  }
  
  if (action.type === 'DECREMENT') {

dewey92

// ...

const Counter = () => {
  // ...
  
  const decr = () => {
    if (state === 0) {
      alert('Ya akhi, nilai counter ndak boleh di bawah 0 😚');
    } else {
      dispatch('DECREMENT');

dewey92

// Counter.jsx
import * as React from 'react'
import { useCounterReducer } from './useCounterReducer'

const Counter = () => {
  const [counter, dispatch] = useCounterReducer();
  
  React.useEffect(() => {
    if (counter < 0) {
      alert('Ya akhi, nilai counter ndak boleh di bawah 0 😚');

dewey92

// useCounterReducer.js
import * as React from 'react';

const counterReducer = (state, action) => {
  if (action.type === 'INCREMENT') {
    return state + 1;
  }
  
  if (action.type === 'DECREMENT') {
    return state - 1;

dewey92

const map = <F, A, B>(fn: (val: A) => B, thing: F<A>): F<B> = /* IMPL */;

dewey92

type Tree<A> = Leaf<A> | Branch<A>
type Leaf<A> = {
  kind: 'leaf';
  value: A;
}
type Branch<A> = {
  kind: 'branch';
  left: Tree<A>;
  right: Tree<A>;
}

dewey92

interface Array<T> {
  map: ...
  filter: ...
  reduce: ...
  length: number;
  ...
}
const names: Array<string> = ['jihad', 'waspada']
const odds: Array<number> = [1, 3, 5, 7]
// etc