delvalle

class Account {
  private _observers: Observers = new Observers();

  constructor(private _type: string, private _balance: number) {
    this._observers.subscribe(new Observer(`${this._type} balance`));
  }

  get balance() {
    return this._balance;
  };

delvalle

const fee = (feeAmount: number) => {
  return function (
    target: Object,
    propertyName: string,
    propertyDescriptor: PropertyDescriptor,
  ) {
    const originalSetter = propertyDescriptor.set;

    propertyDescriptor.set = function (next) {
      const newBalance = next - feeAmount;

delvalle

class Account {
  private _observers: Observers = new Observers();

  constructor(private _type: string, private _balance: number) {
    this._observers.subscribe(new Observer(`${this._type} balance`));
  }

  get balance() {
    return this._balance;
  };

delvalle

type ObserverCallback = (newValue: any) => void;

class Observer {
  constructor(private _subject: string, private _callback?: ObserverCallback) {
  }

  get subject() {
    return this._subject;
  }

delvalle

interface ITransactionDelegate {
  deduct(amount: number, context: Account): void;
}

class Transaction implements ITransactionDelegate {
  deduct = (amount: number, context: Account) => context.balance = context.balance - amount;
}

class Account {
  constructor(private _type: string, private _balance: number) {

delvalle

import React, { Component, ReactNode } from 'react';

type Props = {
  whatAnimal:string,
};

export class Animal extends Component<Props> {
  componentWillMount() {
    // Class Component Lifecycle
  }

delvalle

import React, { ReactElement } from 'react';

interface Customer {
  firstName: string;
}

type Props = {
  customer: Customer;
}

delvalle

// create a regular div and span elements
const div = document.createElement('div');
const span = document.createElement('span');
span.id = 'span_id';
// appending the span element under the div
div.appendChild(span);
// append the div into the DOM
document.body.appendChild(div);

// will output HTMLDivElement {}

delvalle

import 'reflect-metadata';
import { ApolloServer } from 'apollo-server-express';
import express from 'express';
import { buildSchema } from 'type-graphql';

import { init_db } from './database/init_db';
import { Resolvers } from './schema/Resolvers';

const main = async() => {
  await init_db();

delvalle

{
  "type": "sqlite",
  "database": "./src/database/database.sqlite3",
  "entities": [
    "./src/models/index.ts"
  ]
}