r3dm1ke

import React, {useState, useMemo, useCallback} from 'react';

function App() {
  const [length, set_length] = useState(3);
  const [name, set_name] = useState('John Doe');

  const on_name_changed = useCallback((e) => set_name(e.target.value), []);
  const on_length_changed = useCallback((e) => set_length(Number(e.target.value)), []);

  return (

r3dm1ke

import React, {useState, useMemo} from 'react';

function App() {
  const [length, set_length] = useState(3);
  const [name, set_name] = useState('John Doe');

  return (
    <>
      <input value={name} onChange={e => set_name(e.target.value)} />
      <NameDisplay name={name}/>

r3dm1ke

import React, {useState} from 'react';

function App() {
  const [length, set_length] = useState(3);
  const [name, set_name] = useState('John Doe');

  return (
    <>
      <input value={name} onChange={e => set_name(e.target.value)} />
      <NameDisplay name={name}/>

r3dm1ke

// Declaring variables

// ReasonML has immutable variables by default
let name = 'Michael';

// Has the same syntax for object destructuring
let {user, password} = request;

// Control flow

r3dm1ke

let sum = (a, b) => a + b;

// ReasonML knows that the + operator is only applicable to integers
// (every type has its own operators), so this results in:
let sum = (a: int, b: int): int => a + b;

r3dm1ke

function add(x, y) {
  return x + y;
}

// Type inference in TypeScript will result in this:
function add(x: any, y: any):any {
  return x + y;
}

r3dm1ke

function abacaba() {
    return
    {
      a: 'b'
    }
}

console.log(abacaba());

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x = 'abacaba'; // using an undeclared variable is not allowed in strict mode

delete x; // deleting variables is also not allowed

function(x1, x1) {} // duplicating argument names is not allowed

r3dm1ke

// the function itself
function getData(callback, errorCallback) {
  try {
    // Do some network/api stuff...
    callback(result)
  } catch (e) {
    errorCallback(e);
  }
}

r3dm1ke

function Car(name, make) {
  // Here, this is not a reference to outer object
  // But a placeheloder object you can use to construct the
  // desired value
  this.name = name;
  this.make = make;
  // you do not have to return anything, as this is automatically returned
}

const myCar = new Car('Outback', 'Subaru');