MauricioRobayo

import { ComponentPropsWithoutRef, ElementType, ReactNode } from "react";
import "./styles.css";

interface Component1Props<T extends ElementType = "div"> {
  as?: T;
  children: ReactNode;
}
type Props<T extends ElementType> = Component1Props<T> &
  Omit<ComponentPropsWithoutRef<T>, keyof Component1Props<T>>;
function Component1<T extends ElementType>({ children, as }: Props<T>) {

MauricioRobayo

It's much easier to recover from no abstraction, than the wrong abstraction.

Abstractions come with a significant cost and a significant risk.

It's better to under-abstract to begin with.

Start with a few abstractions and lots of repetitions. Find repetitive patterns. If the pattern doesn't lead to bugs, don't fix it. It might look ugly but it's not hurting anyone. Try to generalize it and you risk adding bugs in the generalization. It only adds surface area to everyone.

MauricioRobayo

The initialState argument is the state used during the initial render. In subsequent renders, it is disregarded. If the initial state is the result of an expensive computation, you may provide a function instead, which will be executed only on the initial render:

MauricioRobayo

type PromiseReturnType<T> = T extends Promise<infer R> ? R : T;

MauricioRobayo

Absence of structure is more structured than bad structure.

MauricioRobayo

export function isNextMondayHoliday(date: Date): boolean {
  const currentDate = new Date(date);

  do {
    currentDate.setUTCDate(currentDate.getUTCDate() + 1);
  } while (currentDate.getUTCDay() !== DayOfWeek.MONDAY);

  return isHoliday(currentDate);
}

MauricioRobayo

So next time you're maintaining the state of your app and trying to figure out a synchronization bug, think about how you could make it derived on the fly instead.

MauricioRobayo

Lookahead

The syntax is: X(?=Y), it means "look for X, but match only if followed by Y". There may be any pattern instead of X and Y.

For an integer number followed by %, the regexp will be \d+(?=%):

MauricioRobayo

const Direction = {
  Up: 0,
  Down: 1,
  Left: 2,
  Right: 3,
} as const;

type Direction = typeof Direction[keyof typeof Direction];
function run(dir: Direction) {}

MauricioRobayo

Use a service layer for your business logic.

In this layer there should not exists any form of 'SQL query', use the data access layer for that.

- Move your code away from the express.js router
- Don't pass the req or res object to the service layer
- Don't return anything related to the HTTP transport layer like a status code or headers from the service layer.